Proceedings of the 2nd International Symposium on Erosion in SouthEastern Nigeria held at the Federal University of Technology Owerri Nigeria under the Auspices of the European Economic Council EEC – Table of Content

Proceedings of the 2nd International Symposium on Erosion in SouthEastern Nigeria held at the Federal University of Technology Owerri Nigeria under the Auspices of the European Economic Council EEC – Table of Content

(1.) Bonus, M., 1992. Soil Erosion under Traditional Farming Systems, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.01, volume 2(1);p.11.

SOIL EROSION UNDER TRADITIONAL FARMING SYSTEMS

BONUS, M.

Department of Soil Science, School of Agriculture, University of Cape Coast, Cape Coast Ghana

ABSTRACT

The traditional farming system of shifting cultivation has become inefficient in recent times as a sustainable system because of the decreased fallow period from 10-6 years to 2-3 years due to increased population pressure on agricultural lands. The peasant cropping systems do have some aspect of soil conservation embodied in them. However, many research efforts have not been directed towards assessing the potential of these cropping systems as a soil conservation tools. Thus, there is a scarcity of information on erosion under traditional farming systems. It is rather sad that many years of research efforts attempting to find replacements for the tradition farming systems have failed because the socio-economic environment in which the traditional farmer operates has not been considered as critical. Most of the so-called improved farming systems for soil conservation were developed without understanding the priorities of the traditional farmer. For instance, the no-tillage concept was known to the traditional farmer before research began to improve the technology. A question could be asked whether or not the traditional farmer has accepted the new concept of no-tillage at the expense of what he already knew. Definitely, the answer is negative. In this paper, an attempt has been made to provide some quantitative information on erosion under some traditional farming systems. Furthermore, some alternative technologies that could be useful in improving the traditional farming systems have been proposed. The data provided indicate that we have to begin with what the traditional farmer knows and try to help him improve his known technology rather than attempting to impose foreign technologies on him. Using this bottom-up approach, there is a likelihood that we would succeed in our search for sustainable farming systems to replace the traditional ones.

(2.) Grabs, W. E., 1992. Interdependence Analysis of Geological and Socio/Economic Variables As A Planning Tool For Soil Erosion Control In Southeastern Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/MD.01, volume 2(1); p.12-13.

INTERDEPENDENCE ANALYSIS OF GEOLOGICAL AND SOCIO/ECONOMIC VARIABLES AS A PLANNING TOOL FOR SOIL EROSION CONTROL IN SE-NIGERIA

GRABS, W.E.

German Agency for Technical Cooperation (GTZ),

Bergstr. 41­, D-55584 Bullay/Mosel, Federal Republic of Germany.

Abstract

The continued loss of farmland for food production due to severe sheet and gully erosion and the simultaneous increase of population in SE-Nigeria leads to the imminent danger of a geo-ecological collapse and severe nutritional consequences for large parts of the rural population. In the planning of soil erosion control measures, much emphasis has in past studies been laid on geological and geomorphologic variables, while socioeconomic factors were largely neglected. While regression analysis has been widely used, the analysis of the interdependence of (static) geological/geomorphologic and (dynamic) socio-economic variables has rarely been conducted. These interdependencies however are the effective control mechanisms that influence the extent and activity of the dynamic soil erosion processes. In a case-study in Eastern Nigeria,  it is demonstrated how the analysis of interdependence between key variables that influence soil erosion can be used as an operational tool for the planning of measures against soil erosion. In a study region of 555sqkm which includes the Agulu – Nanka soil erosion area, principal component analysis of 10 key geological, geomorphologic and socio-economic variables has been carried out in a Geographical Information System (GIS) to determine the principal factors of soil erosion. It could be shown, that while soil erosion is closely linked to geomorphological variables on the Awka-Umuduru escarpment, the dynamic development processes of soil erosion are almost exclusively determined by a human land management (farming systems, infrastructure, settlement patterns) with population pressure as a principal cause of further erosional deterioration of the environment. The computation of the factor-value for each GIS-cell allows the mapping of the severity of each factor in each GIS cell. On this basis, a base- map of factor values could be compiled that allows the priority-oriented, spatially adequate planning of strategic and tactical measures of control measures against soil erosion. A catalogue of principal control measures for each GIS-cell of the study area is presented on the basis of this planning map. Once the data has been entered in the GIS, this method allows effective monitoring of the development of soil erosion and an appraisal of the effectiveness of control measures.

(3.) Iwugo, K. O., 1992. Impact of Soil Erosion on Water Quality: New Dimensions Of An Age-Old Problem, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/WQ.01, volume 2(1); p.13-14.

IMPACT OF SOIL EROSION ON WATER QUALITY: NEW DIMENSIONS OF AN AGE-OLD PROBLEM

IWUGO, K.O.

Department of Civil Engineering, University of Lagos, Akoka Lagos Nigeria

Abstract

Land is a primary resource base for sustainable development and its abuse or degradation is not new in human history; the “dust bowl” in the United States in the 1930s and the more recent phenomenon of desertification of the Sahel are well documented cases of land degradation. Desertification and landslide are examples of extreme forms of land degradation and soil erosion is a major causative factor. Soil erosion which is the most basic type of land degradation involves the detachment, transportation and deposition of soil particles by agencies such as water, wind and gravity. Weathering (causing geologic erosion), tillage, trampling and various other biotic (e.g. deforestation) and industrial activities (causing accelerated erosion) are the main soil detachment processes. Surface runoff and wind are among the important transporting agents. Land and water bodies are the major receptors of the detached and transported soil particles. Considering the aforementioned mechanism of soil erosion in conjunction with the conventional hydrological cycle, the traditional cause – effect relationship between soil erosion and water quality (the physical, chemical and biological characteristics affecting water use) becomes easily discernible. Although tropical rivers are characterized by high sediment load (high concentration of suspended solids), which undoubtedly is attributable to the high erossivity of intense tropical precipitation, systematic scientific investigations and research on the direct effect of soil erosion on water quality are either totally lacking or very recent even on a global context. Systematic scientific investigation and research in a close area of “Storm Water Runoff quality and the Ecological effects upon receiving Waters” is also very recent and date back only to the mid 1970s. This paper presents an overview of the technical and socio-economic aspects of land degradation with special emphasis on soil erosion and then attempts to highlight the possible impacts of soil erosion on the quality of storm water and the receiving surface waters. The paper also suggests practical technical control measures for the quality of storm water runoffs; and also practical institutional framework for water quality management in the context of soil erosion in Nigeria.

Keywords: Land degradation; soil erosion; storm water quality; control measures; institutional framework.

(4.) Onwuka, G.M and B.A Nwachukwu., 1992. Roadside Erosion In Southeastern, Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/ST.02, volume 2(1); p.14 -15.

ROADSIDE EROSION IN SOUTHEASTERN NIGERIA

ONWUKA, G.M AND NWACHUKWU, B.A.

Federal University of Technology, Owerri

Abstract

The study presented in this paper shows the seriousness of roadside erosion in the south-eastern states of Nigeria. In the study, a detailed mapping of eroded sites was conducted. The initial design was assessed for adequacy of anti-erosion measures and as-built work was determined. It was consequently discovered that roadside erosion in the study areas has design, construction and maintenance components. The study identified three major classes of roadside erosion namely sheet, gully and rill, which occurred largely on the slopes. It was found that lack of maintenance after commissioning of a road project is one of the major causes of roadside erosion which has now resulted in the development of an erosion problem of disastrous proportion in this region. Other major causes of roadside erosion include lack of drainage at the necessary length of the road, numerous entries/exits from the highways to villages and compounds and lack of vegetation on the shoulders and the slopes. In the concluding section, this paper advocates some roadside erosion control measures – both structural and non-structural. It also laid emphasis on seeding provision of drainage and limiting the access to highways.

(5.) Edide, I.O., 1992. Investigation of Scour and Design of Erosion Prone Aprons – a Case Study, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/ST.03, volume 2(1); p.15.

INVESTIGATION OF SCOUR AND DESIGN OF EROSION PRONE APRONS:

A CASE STUDY

EDIDE, I.O.

Director for Rural Development, Office of the Governor, Calabar, Cross River State, Nigeria

Abstract

In the cause of engineering supervision for Cross River State Directorate of Rural Development (CRS DFRRI), it was observed that all aspects of erosion control have to be addressed in conformity with the soil – structure system of DFRRI Landing Jetties. This paper outlines the corresponding settling paths (CSP) approach in the investigation of scouring along the Henshaw Town Beach, where an open landing jetty facility is under construction for cross River State DFRRI. Also, engineering design to ascertain erosion-prone aprons is included.

(6.) Ijioma, C.I., 1992. Engineering Non Structural Measures For Erodible Soil Stabilization In Southeastern Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/ST.04, volume 2(1); p.15-16.

ENGINEERING NON-STRUCTURAL MEASURES FOR ERODIBLE SOIL STABILIZATION IN SOUTHEASTERN NIGERIA

IJIOMA, C.I.

Department of Agricultural Engineering, Federal University of Technology, Owerri

 

Abstract

In studies to determine the potential for the use of locally produced agricultural by-products in the stabilization of erodible soils in Southeastern Nigeria, Palm Kernel Shell Ash (PKSA) and Rice Husk Ash (RHA) were mixed with the tropical lateritic soils and subjected to various relevant geotechnical tests required in the preparation of earthworks and flood watercourses. The laboratory and field tests results showed that the PKSA and RHA improved the physical behaviour of the soils in terms of rate of settlement and soil loss during overland flow. From the study, it was evident that the two agricultural by-products could be used as substitutes for imported lime used in soil stabilization in Nigeria. The agricultural by-products could be used in minimizing the scouring tendency of soils at culvert outlets or at downstream of check dams.

(7.) Ibiam, A. S.,1992. Geotechnical Properties And Measures For Erosion Control In Ebem Ohafia In Abia State, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/ST.05, volume 2(1); p.16.

GEOTECHNICAL PROPERTIES AND MEASURES FOR EROSION CONTROL IN EBEM OHAFIA IN ABIA STATE

IBIAM, A.S.

School of Environmental Studies, Abia State University Uturu, Okigwe

Abstract

Settlement not properly located, designed, constructed or maintained are subject to serious erosion and other environmental hazards. The geotechnical properties and measures for erosion control in Ebem Ohafia are studied and recommendations preferred. Field studies revealed that the soil varies from sand, silt, clay to gravel. The soil contains calcium, magnesium, potassium and sodium. The percentage organic carbon, organic matter and gravel is very low while the total weights of red soil and white soil are very high. The implications of these findings to soil erosion and control measures are also discussed. Serious erosion results in unsightly conditions and increased maintenance costs and is a safety hazard. The control of soil erosion and runoff is basic to the protection of Ebem Ohafia town. The success of the erosion control measures recommended is very necessary because of the many hectares of land now covered by the erosion menace.

(8.) Agha, H. I., 1992. A Systems Cost Minimization Model For Erosion Control In Road Construction, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/ST.06, volume 2(1); p.17.

A SYSTEMS COST MINIMIZATION MODEL FOR EROSION CONTROL IN ROAD CONSTRUCTION

AGHA, H.I.

School of Engineering and Engineering Technology, Federal University of Technology Owerri

 

Abstract

During the last two decades, the Nigerian construction industry witnessed unprecedented activity in the area of highway development. However, because the erosion control aspects of these roads were either not considered at all in their design and construction, or were only partially considered, these road works have opened up many erosion sites. Many of these sites have grown into gullies of such magnitude that the affected areas are now designated ecological disaster areas. This paper assesses the various factors which contribute to erosion development if not adequately provided for during new road construction. The factors include total run-off from a given catchment area, side drains of appropriate capacity to transport the run-off to safe spots in valley areas or across highways through culverts or bridge structures, road pavements of appropriate widths and strength, and the planting of grass on all exposed surfaces. The inter-relationship among the above factors are reflected in a linear programming systems model which seeks to minimize the cost of erosion control structures during road construction. Each of the factors is represented along with its cost coefficient in a linear objective function. The function is then minimized subject to certain constraints. The constraints are inequalities based on highway design and construction code requirements, the amount of fill, total run-off into the valley area being designed for, the necessary length and capacity of drainage structures, and the specified vertical alignment for the given road segment. The linear programming system’s model is solved using Dantzig’s simplex algorithm. The set of linear constraint boundary-functions is viewed as forming a multidimensional simplex or convex cone which encloses the entire set of feasible solutions. The values of the variables which results from the simplex solution are then substituted in the objective function to determine the minimum cost of the erosion control structures which must be in place to check erosion.

(9.) Mungai, D. N. ,1992. The Potential Role Of Alley Cropping In Enhancing Sustainable Crop Production Under Tropical Semi-Arid Conditions, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.02, volume 2(1); p.18.

THE POTENTIAL ROLE OF ALLEY CROPPING IN ENHANCING SUSTAINABLE CROP PRODUCTION UNDER TROPICAL SEMI-ARID CONDITIONS

MUNGAI, D. N.

Department of Geography, University of Nairobi, P.O. Box 30197 Nairobi, Kenya

 

Abstract

Recent micro-meteorological research aimed at assessing the potentials of alley cropping under semi-arid conditions in Eastern Kenya is described. The results that were obtained are presented and discussed. The role of agro-forestry in soil protection from water and /or wind particularly on sloping lands under semi-arid conditions is highlighted.

(10.) Opara, C.C And N.A. Ozara.,1992. Multi-Storey Cropping System For Controlling Soil Erosion In Southeastern Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.03, volume 2(1); p.18-19.

MULTI-STOREY CROPPING SYSTEM FOR CONTROLLING SOIL EROSION IN SOUTHEASTERN NIGERIA

OPARA, C.C. AND N.A. OZARA

Department of Crop Production, School of Agriculture and Agricultural Technology, Federal University of Technology, Owerri, Imo State

 

Abstract

Soil erosion in form of splash, sheet, rill and gully has become a major feature of the Southeastern Nigerian Landscape. Control measures include agronomic, soil management and mechanical methods. However, agronomic measures which involve the use of vegetative cover in protecting the soil have often been neglected due to maybe doubts about their relevance and efficacy. This may be true especially when they are not well designed and executed. This paper examines the attributes of multi-storey cropping as they relate to soil erosion control in Southeastern Nigeria. Some field data on arable multi-storey cropping in Southeastern Nigeria are presented. Other soil management practices for effective soil conservation are proposed and recommendations made.

(11.) Atu, U.G., Okere, P.N., Palte, H., Osuji, G.E. And Mollema, A., 1992. Assessment Of Some Plants For Ground Covers In Erosion Control In Southeastern Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) 1992, Paper ISE/SEN/92/FA.04, volume 2(1); p.19.

ASSESSMENT OF SOME PLANTS FOR GROUND COVERS IN EROSION CONTROL IN SOUTHEASTERN NIGERIA

ATU, U.G., OKERE, P.N., PALTE, H., OSUJI, G.E. AND MOLLEMA, A.

Erosion Research Centre, Federal University of Technology, Owerri

Abstract

Adequate ground cover by plants effectively reduces soil erosion, especially on sloping lands. Giant star grass, guinea grass, Pueraria and style consistently maintained 100% ground cover after one year of the establishment; re-growth was however fast in guinea grass and giant star grass after bush burning. Soil loss in tones per hectare was for guinea grass, 26.9; giant star grass, 40.0; Centrosema, 96.9; mucuna 75.0; stylo 49.4 and Pueraria 37.5. Of all the plants, stylo remarkably suppressed plant-parasitic nematode population from the soil, while Pueraria tripled the pre-plant population. Giant star grass was resistant to termite attack during the dry season, followed by guinea grass and stylo.

(12.) Okorie, P.E. , 1992. Plants For Erosion Control (A Silviculturist View Point), Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.05, volume 2(1); p.20.

PLANTS FOR EROSION CONTROL (A SILVICULTURIST VIEW POINT)

OKORIE, P.E.

Abstract

An interdisciplinary approach, especially the combination of engineering and afforestation methods is necessary for the control of advanced soil erosion. Reclamation of sheet erosion sites as well as protection of the environment can be accomplished mainly through the provision of vegetation cover. Choice of suitable available plant species is critical for the success of these biological methods. Past and present research efforts have been directed towards the choice of suitable indigenous and exotic tree and non-tree species to suit the wide range of climates, terrains, and soil types found in different parts of Nigeria. This paper outlines the characteristics of plant species used for erosion control and discusses the silvicultural implications of especially, the exotics Pinus Caribaea Ex Honduras, Gmelina Arborea Roxb and Eucalyptus sp. currently in use in Nigeria. The merits and demerits of exotics and indigenous species are also discussed.

(13.) Okereke, C.D.,1992. Effect of Certain Inorganic And Organic Matter On Soil Detachability, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.06, volume 2(1); p.20-21.

EFFECT OF CERTAIN INORGANIC AND ORGANIC MATTER ON SOIL DETACHABILITY

OKEREKE, C.D.

Project Manager, Gully Erosion Afforestation Project Forestry Research Institute, P.M.B 01097, ENUGU

 

Abstract

Soil samples collected from Osina, Orlu and Urualla areas were characterized. 2 kg weight of soil samples from the 3 locations were each given five different treatments with 0%, 5%, 10%, 15% and 20% proportions by weight of rice husk (RH), poultry manure (PM) and NPK 15:15:15 fertilizer, respectively. After each of the treatments (mixing soil with proportions of additive), the treated soils were put in separate bowls and allowed to stay at room temperature for six weeks. Thereafter, the PH, organic matter content, direct shear strength and soil splash tests were carried out on each treated soil using standard methods. The result showed that the soils are acidic and the addition of poultry droppings (manure) increased the soil’s PH by 200% whereas, for same percentage treatment, rice husk and NPK fertilizer increased the soil PH by the smaller magnitude of 20-60%. PM treatment at 95% confidence level availed the highest organic matter followed by RH and NPK in that order. The highest soil detachability measured in terms of soil splash was observed in the RH treatment followed by PM and NPK. 5% additive treatment is the optimum for least detachability (splash). The discussions on the various trends are presented.

(14.) Obiefuna, J.C and I.C. Onwueme., 1992. Mango Orchards For The Rehabilitation Of Reclaimed Gulleys In The Tropics, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.07, volume 2(1); p.21.

MANGO ORCHARDS FOR THE REHABILITATION OF RECLAIMED GULLEYS IN THE TROPICS

 

OBIEFUNA, J.C.  AND I.C. ONWUEME

Federal University of Technology, Owerri

Abstract

Mango (Mangifera indica cv Lindissina) was established on Lake Nwaebere Campus of the Erosion Research Centre project site. The establishment, growth, and canopy development and fruit yield of the trees were monitored annually while soil loss and litter build-up were monitored at the beginning and end of each rainy season for six consecutive years using graduated spikes. The result shows that loss reduced with time as canopy litter drop increased. The soil organic matter also increased, while the weed population under the mango canopy reduced. Several other biological activities were stimulated which may have collectively contributed to the soil stabilization and increased soil fertility.

(15.) Aririatu, L.E And J. Iwuagwu., 1992. Ecological Aspects Of Soil Disintegration, A Possible Biological Markup For Erosion Prone Zone, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.08, volume 2(1); p.22.

ECOLOGICAL ASPECTS OF SOIL DISINTEGRATION, A POSSIBLE BIOLOGICAL MARKER FOR EROSION PRONE ZONE

ARIRIATU, L.E.

Department of Biological Sciences, Federal University of Technology, Owerri

and

C. J. IWUAGWU

Department of Geosciences, Federal University of Technology, Owerri

Abstract

The biomass and the standing crop of Okwudor gully erosion site (Benin Formation), the Umunna Sandstone Member of Imo Shale Formation, and a sandstone layer of the Bende-Ameki Formation were determined by standard ecological and microbiological methods. Preliminary results show very little biological activity and low energy level amongst the various trophic levels in the various habitats examined. The average number of micro-organisms in the profile of the adjoining soil at Okwudor is 4.9 x 109/g for bacteria and 3.7 x 104/g for fungi, whereas the Okwudor gully had 3.0 x 104 / g, and both sandstone units (Umunna sand-stone and Bende-Ameki Formation) had an average of 3.0 x 103/g for bacteria. Fungi were absent in both the gully and the sandstone deposits whereas algae averaged 6.37Kcal/g dry weight in the sandstone units but were absent in the Okwudor gully. Standing biomass represents stored energy in a habitat or ecosystem. The low biomass recorded in the Okwudor gully and the two sandstone units examined indicate low gross results indicate low gross primary productivity. The results indicate that low stored energy levels and low gross primary productivity in the habitats are some of the biological variables implicated in soil disintegration and erosion.

(16.) Madubuike, C.N and G. O. Chukwuma., 1992. Relative Susceptibility Of Some Southeastern Nigerian Soils To Erosion By Water, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/FA.09, volume 2(1); p.23.

RELATIVE SUSCEPTIBILITY OF SOME SOUTH EASTERN NIGERIAN SOILS TO EROSION BY WATER

MADUBUIKE, C.N.

Department of Agricultural Engineering, Erosion Research Centre, Federal University of Technology, Owerri

and

G. O. CHUKWUMA

Department of Agricultural Engineering, University of Nigeria, Nsukka

 

Abstract

In-situ rainfall simulator runs were carried out on 15 soil groups located in various parts of southeastern Nigeria. The tests were carried out under dry, wet, and saturated soil conditions, each at rainfall intensities of 90, 60 and 40mm/hr. The resulting soil losses were analyzed and the relative susceptibility of the various soil groups to erosion by water determined based on the average rate of soil loss. The results show the soil group susceptibility in decreasing order to be: Eutric Nitosol (Typic Tropudalfs); Ferric Acrisol (Typic Tropudult); Orthic Acrisol ( Typic Hapludult); Dystric Cambisol (Typic Dystropepts); Dystric Gleysol (Typic Tropaquept); Dystric Nitosol (Typic Paleudult); Dystric  Nitosol (Arenic Paleudult); Eutric Gleysol (Typic Tropaquept); Plinthinc Acrisol (Plinthic Tropudult); Eutric Fluvisol (Eutric Tropofluents); Dystric Fluvisol (Typic Tropudult); Dystric Cambisol (Typic Dystropepts); Dystric Nitosol(Gross Arenic Paleudult); Dystric Cambisol(Typic Dystropepts) and Dystric Nitosol(Aquic Paleudult).  A result such as this will prove very useful in land-use planning and policy formulation in erosion prevention and control strategies in the region studied.

(17.) Iwuagwu, C.J and Onu, N.N., 1992. Characterization Of Soils In The Erosion Prone Areas Of S.E Nigeria: A Case Study Of The Bende-Ameki Formation, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/MD.002, volume 2(1); p.24.

CHARACTERIZATION OF SOILS IN THE EROSION PRONE AREAS OF SOUTHEASTERN NIGERIA: A CASE STUDY OF THE BENDE-AMEKI FORMATION

IWUAGWU, C.J. AND ONU, N.N

Department of Geosciences, Federal University of Technology, Owerri Imo State Nigeria

Abstract

Geological and geophysical studies were carried out on the sediments of the Bende-Ameki Formation of Southeastern Nigeria. The objective was to determine the extent to which these soils are susceptible to erosion. Our approach was to determine the petrophysical characteristics of the sediments and to locate possible fractures or faults zones and relate these to gully initiation. Results indicate that soils of high porosity and permeability which are lacking in cementing materials are underlain by clays which confine water. The implications of these on gully initiation are discussed in this paper.

(18.) Onu, N.N and Ananaba, S.E., 1992. Gully Erosion And Neo-Tectonism In Southeastern Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/MD.003, volume 2(1); p.24-25.

GULLY EROSION AND NEO-TECTONISM IN SOUTHEASTERN NIGERIA

ONU, N.N AND ANANABA, S.E.

Department of Geosciences, Federal University of Technology, Owerri, Imo State Nigeria

Abstract

This paper attempts to relate major gully erosion sites in parts of Southeastern Nigeria to mapped tectonic trends in these areas. A base map of lineaments has been produced at a scale of 1:50,000 and the known erosion sites approximately located. Limited geophysical survey has been carried out at selected sites in Umuagor Urualla, Okwudor and Ihiagwa, in order to confirm the mapped tectonic trends. The results show that although the gully erosion in parts of S.E Nigeria is very often associated with cultural activities (exogenic processes), the very deep gullies which almost defy all control measures seem to occur along major fracture zones in these areas. Their increasing intensities seem to suggest that these ancient fracture zones are indeed being reactivated; a sort of neo-tectonism. The implications of this suspicion on gully control are hereby discussed.

(19.) Ozara, N.A., 1992. A Model For Designing Crop Management Systems For Humid Tropical Environments, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/MD.004, volume 2(1); p.25.

A MODEL FOR DESIGNING CROP MANAGEMENT SYSTEMS FOR HUMID TROPICAL ENVIRONMENTS

OZARA, N.A.

Department of Crop Production and Soil Science,  Federal University of Technology, P.M.B. 1526 Owerri.

Abstract

A model is presented that meets some of the soil conservation needs of the humid tropical environment. The model addresses the problems of rainfall and soil data scarcity as well as farming peculiarities of the region. The model AMELUP – is distributed, event-based and is based on the agronomic principles of erosion control and soil conservation. It is applicable to farm fields, erosion plots and small catchments. The major components simulated include hydrology, soil erosion and crop/residue management systems. A sensitivity analysis of the vegetative parameters showed that soil loss and runoff are sensitive to the amount of surface biomass, canopy density and depth of rooting of the previous crop. Some planning scenarios with AMELUP using hypothetical conditions are presented to demonstrate the rationality of the structure and capabilities of the model.

(20.) Nill, D., 1992. Determination Of Soil Erodibility For Soils Of Humid And Sub-humid West Africa, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/MD.005, volume 2(1); p.24-25.

DETERMINATION OF SOIL ERODIBILITY FOR SOILS OF HUMID AND SUB-HUMID WEST AFRICA

DIETER NILL

IITA/GTZ/IRA/TU-Munich Project ‘Soil erosion studies in the humid tropics’

Lehrstuhl fur Bodenkunde Technische Universitat Munchen D-8050 Freising/Weihenstephan

Abstract

K factors of representative soils have been measured under natural and simulated rainfall conditions in Cameroon and Nigeria for several years. Calibration plots for the comparison of the two methods showed a good agreement between K factors measured under natural and simulated rainfall conditions. Long-term K factor variation and estimations for the residuals sub-factor of the USLE for humid savanna and rain forest are presented. The use of soil properties for the determination of K factors is discussed.

(21.) Breuer, J., 1992. Inefficiency of Erosion Control Measures on Hard Setting Soils in Northern Cameroon, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/WQ.001, volume 2(1); p.26-27.

INEFFICIENCY OF EROSION CONTROL MEASURES ON HARDSETTING SOILS IN NORTHERN CAMEROON

BREUER JORN

Lehrstuhl fur bodenkude technische univeristat munchen d- 8050 freising / weihenstephan

and

DIETER NILL

Institute de recherché Agronomique Centre National de Sols Maroua, Cameroon

Abstract

Hard setting soils occurring in northern Cameroon have a very low structural stability and water permeability and are hard and structureless when dry. They are classified as Alfisols and Inceptisols with aquic soil moisture regime and occur in low (alluvial) landscape positions. The profiles show bleached topsoils, iron and manganese mottling in the subsoils and an abrupt clay increase with depth. Agricultural use of hard setting soils is impeded by low infiltration, soil erosion and soil hardening causing poor germination. Surface applied measures to improve soil infiltrability (mulching, CaS04) were effective on crusting soils but not effective on hard setting soils. It is postulated that the poor aggregation due to lack of stabilizing soil components (organic matter, (Iron)Fe oxides ) leads to slaking of the soils during the rainy season followed by setting and hardening on drying. In research and extension projects, hard setting soils should be mapped as an own category based on their physical behaviour independent of the soil classification system. Land use and re-cultivation systems for hard setting areas have to be developed.

(22.) Nwankwor, G.I. And C.J. Iwuagwu.,1992. A Preliminary Evaluation Of Piping – Quick Condition Phenomena As Factors In Gully Expansion: Amucha Gully, Imo State, Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/MD.006, volume 2(1); p.27-28.

A PRELIMINARY EVALUATION OF PIPING – QUICK CONDITION PHENOMENA AS FACTORS IN GULLY EXPANSION: AMUCHA GULLY, IMO STATE, NIGERIA

 

NWANKWOR, G.I. AND C.J. IWUAGWU

Department of Geosciences, Federal University of Technology, Owerri

 

Abstract

Hydraulic head gradients were determined from a network of piezometers installed along with the groundwater flow system at Amucha, in the River Njaba drainage basin for purposes of evaluating the importance of seepage forces in the gullying process. The hydraulic gradient was between 0.15 and 0.19 but increased to 0.35 after a rainfall event, thus giving a seepage force magnitude of 3.43 KN. On the basis of measured void ratio values that ranged from 0.6 to 0.9, and an assumed but typical particle density of 2.65 Mg/m3, the critical hydraulic gradient required to initiate piping / quick condition is 0.8 (or 7.8 KN). This is much higher than the calculated head gradient and would seem to suggest that piping and quick conditions are not important in the gullying process. However, the near three-fold increase in the hydraulic head gradient after just one rainfall event would seem to suggest that critical gradients may readily be attained during the rainy season when rainfall is more frequent and intense.

(23.) Vermeulen, H.R and T. H. M. Rientjes., 1992. Kinematic Modeling of Surface Runoff in a Geographic Information System, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/MD.007, volume 2(1); p.28.

KINEMATIC MODELING OF SURFACE RUNOFF IN A GEOGRAPHIC INFORMATION SYSTEM

VERMEULEN, H.R. AND RIENTJES, T.H.M

The Delft University Of Technology, The Netherlands

Abstract

River basin management and the design of various water and erosion control works require proper estimates of overland flow and river flow as generated by heavy rainstorms. A pronounced example is the compilation of erosion hazards maps. Frequently, direct flow measurements are scarce if not absent, urging for indirect methods to assess the magnitude of floods using only readily available data such as rainfall and topographic maps, aerial photographs or remote sensing images. This paper deals with the application of the kinematic wave equation to the modelling of overland flow at the pixel level in a Geographic Information System with altitude levels and rainstorm patterns as basic input and with the subsequent routing of flow to the points of interest at the considered river or gully. Since the model in its present stage does not account for the effect of other physiographic features on the runoff process, its use is restricted to floods from hilly or mountainous watersheds. On a regional scale, where physiographic properties (e.g. soil types and vegetation) and cultural practices (e.g. agricultural) can be regarded as uniform, the adoption of a single calibration parameter suffices to obtain realistic results.

(24.) Deelstra, J., 1992. Methods to Measure Runoff, Erosion and Nutrient Loss from Agriculture, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/WQ.002, volume 2(1); p.29-30.

METHODS TO MEASURE RUNOFF, EROSION AND NUTRIENT LOSS FROM AGRICULTURE

 

DEELSTRA, J. AND QYGARDEN, L.

Jordforsk N-1432 As, Norway

 

Abstract

Jordforsk is a research institute in Norway. One of our main working areas is environmental problems related to agriculture. To quantify the amount of erosion and nutrient loss from agricultural lands, Jordforsk is carrying out measurements from a large catchment area of 700 ha. Inside this area, we have selected a smaller catchment area of 10 ha. Inside this area, 4 plots (USLE-type) of 125 m2 have been established. At each level, we use a different combination of discharge measurement and water sampling. Different systems can be used to measure runoff, erosion and nutrient losses from small USLE-type plots. A problem with conventional discharge measurement structures is their inability to measure small discharge. At the same time, there are often sedimentation problems in the measurement structure before water samples had been taken. Therefore, a tipping-bucket was chosen for these types of measurements. The tipping bucket operates as a discharge measurement structure. Every 10 minutes, the number of tips is stored automatically using a data-logger. As a back-up, a mechanical counter is installed. A simple arrangement is constructed to collect an aliquot sample of the runoff water. For small catchment areas, an RBC-flume is used. One of the reasons for choosing this flume is its capability of transporting sediments. There will be fewer sedimentation problems in the measuring structure compared to e.g. a V-notch. Water levels are automatically recorded, using a float connected to a pot meter. A data logger is used for storing data. At the same time, the logger is programmed to steer water sampling. Recorded water levels are transferred into discharge values. These are used for calculating the amount of water passed. Whenever the amount of water outflow becomes bigger than a certain preset volume, a signal is sent to a water sampler. A magnetic valve, fixed to the flume, is used as a steering unit for the water sampler. The opening time of the sampler is automatically adjusted as a function of the water level in the flume. The sample water is stored in a plastic container. In this way, an aliquot sample is obtained from runoff water. The whole system is operated by a 12 V-battery (DC), which will in case of no discharge is dormant to save battery power. Besides automatic recording, a mechanical recorder is used as a back-up for water level recording.  For large catchment areas, a Crump-weir is used. The characteristics concerning sediments are the same as for the RBC-flume. The system for measuring discharge and water sampling is the same as for small catchments.

(25.) Adeoye , A., 1992. Siltation Problems in the Kadawa Irrigation Scheme, Kano Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/WQ.002, volume 2(1); p.30.

SILTATION PROBLEMS IN THE KADAWA IRRIGATION SCHEME, KANO.

ADEWALE ADEOYE

Department Of Water Resources and Environmental Engineering, Ahmadu Bello University Zaria

Abstract

Siltation is the biggest single physical problem afflicting the operation and performance of many irrigation systems throughout the world. Silt introduced by the water supply builds up on canal beds causing water levels to rise and conveyance capacities to decrease. It has been identified that the data on sediment discharge on which the design of most irrigation canals in the savanna of Northern Nigeria are based are generally scanty and inconsistent. In this paper, the results of a survey of the Kadawa irrigation system in Kano State is presented and analyzed. It was found that the hydraulic efficiency of the canals has dropped to about 62% of its design value due to siltation and weed infestation. Also, Manning’s Roughness Coefficient and other channel properties have changed adversely. Structural, maintenance, and non- structural measures to revamp the scheme are described. A programme of data collection for improvements in the design of fluvial channels in the area is prescribed.

(26.) Nwachukwu, B.A., 1992. Application of the Universal Flow Diagram For Prediction Of Canal and Channel Erosion, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/WQ.004, volume 2(1); p.31.

APPLICATION OF THE UNIVERSAL FLOW DIAGRAM FOR PREDICTION OF CANAL AND CHANNEL EROSION

NWACHUKWU, B.A.

Department Of Civil Engineering, Federal University Of Technology, Owerri

 

Abstract

The universal flow diagram (UF-diagram) first proposed in 1975 has many applications in the study of channel processes. The diagram developed using dimensional analysis and regression techniques involves five dimensionless flow parameters showing the inter-relationship of the discharge intensity, flow depth, bed materials size and discharge, and channel slope for mobile boundary channels. In this paper, the development of the UF-diagram is presented. Through worked examples, the application of the UF-diagram for prediction of channel changes caused by typical effects of urban development schemes and civil engineering works is illustrated. Predication of the long term effects of these works is considered a necessary first step for the design of economical channel control structures.

(27.) Jagtap, S.S., 1992. Development of Principles for Soil Erosion Mapping In Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/SE.02, volume 2(1); p.31-32.

DEVELOPMENT OF PRINCIPLES FOR SOIL EROSION MAPPING IN NIGERIA

JAGTAP, S.S.

International Institute Of Tropical Agriculture, Oyo Road Ibadan, Nigeria

Abstract

Soil erosion research in different agro-ecological zones of Nigeria over the past 20 years has led to the development of indices and equations for quantitative assessment of soil loss from agricultural fields. Information from well-conducted researches ought to be applied in creating awareness for soil conservation. This preliminary study examines the possibility of generating data for areas where soil erosion research has not been carried out in Nigeria by developing equations and methods through which existing data and information could be extrapolated and subsequently used for soil erosion mapping. Soil erosion mapping would be done using a geographic information system. By so doing, it is hoped that user-friendly information would be provided and this would lead to increased awareness for soil conservation.

(28.) Ibe, K.M., Anyanwu, S and A. Sowa., 1992. Anthropogenic Disturbance of Sedimentary Equilibrium: Gully Erosion and Filling Up of River Beds In Selected Areas In Southeastern Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/SE.03, volume 2(1); p.32.

ANTHROPOGENIC DISTURBANCE OF SEDIMENTARY EQUILIBRIUM: GULLY EROSION AND FILLING UP OF RIVER BEDS IN SELECTED AREAS IN SOUTHEASTERN NIGERIA

 

IBE, K.M. AND S. ANYANWU

Department of Geosciences, Federal University Of Technology, Owerri

and

SOWA, A.

WbI Umwelttechnik, Lohweg 27, 8480 Weiden, Germany

Abstract

In nature, erosion and deposition of sediments are at sites and at rates in a balance determined by the natural attributes of sources rocks and climatic factors. In recent times, however, constant anthropogenic activities in the sedimentary environment have greatly disturbed that equilibrium in many areas. The disappearance of Nwaorie River in Imo State, South-eastern Nigeria has prompted the authors to carry out the investigations presented in this paper. The described phenomenon can be attributed to filling up of the river bed by sediments eroded from the catchment and upstream areas. Therefore, an attempt has been made to show the relationships between population density, constructional, industrial and agricultural activities and soil erodibility. In a large view, intensive deforestation together with an equi-temporal intensification of agricultural activities ranges among the main factors responsible. In the presented case, however, uncontrolled sand dredging activities in the downstream area of Nwaorie River contribute to the hazardous disturbance of the sedimentary equilibrium. Coincidently a rapid deterioration of surface-and ground-water quality can be observed in the observed hydrochemical parameters. The presented study is an example of environmental impacts caused by anthropogenic activities that are symptomatic for the extremely sensitive balance of nature, especially in tropical and sub-tropical areas.

(29.) Okeke, P. N and C.C. Asiabaka., 1992. Socio-Economic Impact Of Erosion – Induced Water Pollution On Selected Communities In Imo and Abia States Of Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/SE.04, volume 2(1); p.33.

SOCIO-ECONOMIC IMPACT OF EROSION – INDUCED WATER POLLUTION ON SELECTED COMMUNITIES IN IMO AND ABIA STATE OF NIGERIA

OKEKE, P.N. AND C.C. ASIABAKA

Erosion Research Centre, Federal University Of Technology, P.M.B. 1526, Owerri Nigeria

Abstract

The paper examines the socio-economic impact of erosion influenced water pollution on eight communities in Imo and Abia States of Nigeria. These communities were selected because their major source of drinking water depended on four erosion-prone Rivers; Njaba, Ikwu, Eme, and Imo. Data were collected using personal observation, individual and group interviews. One hundred and sixty respondents comprising of farmers, and other villagers participated in this study. Results show that 95% of the respondents perceived that pollution deprived them of their source of water for domestic uses. High turbidity of the rivers made them unsuitable for recreational activities such as swimming. It was also found that pollution caused the dearth of fish during the study period. Results also show that flooding along the river banks leads to a premature harvest of crops. The study further found that the cost incurred in buying water treatment chemicals by Water Boards increased by about 5%, coupled with an additional cost of maintaining equipment which depreciated at an accelerated rate. The study concluded that erosion influenced water pollution has an adverse socio-economic impact on people in the eight communities and recommended appropriate control measures to check this problem.

(30.) Umoh, U.T., 1992., Soil Erosion and Water Quality Management In Akwa Ibom State Of Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/SE.05, volume 2(1); p.34.

SOIL EROSION AND WATER QUALITY MANAGEMENT IN AKWA IBOM STATE OF NIGERIA

UMOH, U.T.

Department Of Geography, Federal University Of Technology, Minna

Abstract

Soil erosion occurs in several parts of Nigeria under different geologic, climatic and soil conditions. Akwa Ibom State, located at the southeastern corner of Nigeria, lying between latitudes 4033’ and 5033 north and longitudes 7025 and 8025’ east and experiencing a humid tropical type of climate suffers from ravages of soil erosion at various locations. Soil erosion has some hydrological consequences, therefore, calls for strategies of water quality management. Four sets of factors combine to cause soil erosion in Akwa Ibom State. Surface and groundwater quality are assessed as they are an important component of the natural hydrological cycle which constitute major sources of water for a multiplicity of uses. The erodibility of soils calculated by the monograph method was low and ranged between 0.017 to 0.075 t. ha. hr. ha-1 MJ-1 mm-1. In most locations, the product of low erodibility and high erossivity gave potential soil losses that ranged from 830 to 1900 t/ha//yr. Hydrological consequences of soil erosion include blocking of steam channels, a variation of groundwater level and drying up of streams. Available surface water supply sources are sampled, so also are some boreholes in the study area. Bacteriological, physical and chemical quality of the identified water sources were analyzed and found to be fair while some are hard. Possible pollution of ground and surface water are indicated and realistic treatment/management methods proffered.

(31.) Asiabaka, C.C. and J.E. Njoku., 1992. The Rate of Adoption of Erosion Control Measures Among Farmers In Southeastern Nigeria, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/SE.07, volume 2(1); p.35.

THE RATE OF ADOPTION OF EROSION CONTROL MEASURES AMONG FARMERS IN S.E NIGERIA

ASIABAKA, C.C.   AND J.E. NJOKU

Federal University of Technology, Owerri

Abstract

This study focussed on the rate of adoption of erosion control measures among farmers of Southeastern Nigeria. Data was collected from farmers from Orlu area of Imo State. Orlu erosion axis was selected because some erosion control packages such as alley cropping, contour bunding and planting across the slope have been introduced to farmers in the area. Findings show that the rate of adoption was 80%, while most of the technologies introduced to the farmers were adopted. Data analysis also showed that disseminating erosion control packages were most effective through the use of cooperative societies.

(32.) Eshett, E.T., 1992. Deforestation and Related Problems Of Nigeria’s South-East Agro-Ecological Zone: Which Way Forward Towards Achieving Sustainable Food Production, Proceedings of the Second International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 20-25th September, 1992, Paper ISE/SEN/92/SE.08, volume 2(1); p.36.

CITATION OF DR. SAMUEL CHIDI IWUJI:

THE SCHOOL OF HEALTH TECHNOLOGY LECTURE SERIES LECTURER

Dr Samuel C. Iwuji graduated from the biomedical programmes of the University of Port Harcourt and the University of Lagos, Nigeria where he obtained B.Sc. (Hons.), M.Sc. and PhD degree awards in Human Physiology / Pharmacology. He also had advanced professional training in Public Health; Environmental Health, Science Laboratory Technology and Biomedical Engineering. He is a Fellow, College of Biomedical Engineering and Technology of Nigeria. He is a member of the International Federation of Medical and Biological Engineering (IFMBE), Physiological Society, Environmental Health Officers of Nigeria, etc.

Under the driver of excellence, Prof. F.C. Eze as the substantive Vice-Chancellor of FUTO, Dr Iwuji was appointed the first Ag. Head, Department of Physiology (2016 – 2017) and in 2017, he was appointed the 4th Ag. HOD, Biomedical Technology. He among other achievements piloted the Department to achieve her first NUC’s full accreditation after 14 years of existence.

His visions have brought innovations that invigorated the culture of academic and administrative excellence in the Department. Consequently, in 2018, School of Health Technology under the motherly Deanship of Rev. Sr. Prof E.T. Oparaocha gave him the distinguished Merit Award of the School.

He is the pioneer President, Society for Tissue Engineering and Regenerative Medicine of Nigeria (STERMN) and the first LOC Chair that organized the 2018 STERMN International Workshop/ Conference during which STERMN was inaugurated.

He was an active pioneer member of the School of Health Technology (SOHT) Board of studies that nurtured all the Curricula that graduate all the batches of degree-holding health technology professionals since 2008/2009 session. He singly taught and coordinated all Human Physiology and Pharmacology courses in each of the five Departments, including School courses, for many years with excellence.

He was the Immediate Past Chairman, SOHT Lecture Series Committee under our then amiable Dean, Prof I.N.S Dozie. With his leadership by example, he presented the 11th SOHT FUTO Lecture Series and at the same time coordinated the School SIWES programme till 2017. He was also a Sub-committee Chair of SOHT International Conference.

In the Department, he has held all academic and administrative assignments/ appointments, such as the Ag. HOD, Coordinator of Post Graduate programmes, Examinations Officer, Lectures / Time Table Officer, Class and Staff Adviser.

His research and development (R&D) activities are under Physiology and Biomedical Technology, including physiological safety & Impact assessments; bio-instrumentation, safety pharmacology & pharmaceutical technology.

He has been a leader in his Communities. For instances, he is the Chairman of his Town Union Branch. He is the Chairman, ASUU-FUTO Medical and Health Committee, Vice Chairman of a Catholic Station Men’s Organization, among others. He was the immediate past National Secretary of Association of Biomedical Engineering and Technology of Nigeria (NABET). These modest efforts had earned him several awards.

He is gracefully married, with many dependants.

His mission is to create solutions to human health problems. He has successfully supervised/mentored many people, including undergraduates and postgraduates dispersed in different parts of the world.

Signed:

Chairman,

SOHT Lecture Series Organizing Committee

Proceedings of the 1st International Symposium on Erosion in SouthEastern Nigeria held at the Federal University of Technology Owerri Nigeria under the Auspices of the European Economic Council EEC – Table of Content

Proceedings of the 1st International Symposium on Erosion in SouthEastern Nigeria held at the Federal University of Technology Owerri Nigeria under the Auspices of the European Economic Council EEC – Table of Content

(1.) Ofomata, G.E.K., 1988. The Management Of Soil Erosion Problems In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/001, volume 1(1);p.3-12.

THE MANAGEMENT OF SOIL EROSION PROBLEMS IN SOUTHEASTERN NIGERIA

OFOMATA, G.E.K

Department Of Geography, University Of  Nigeria, Nsukka.

ABSTRACT

Soil erosion occurs all over Southeastern Nigeria. As a matter of fact, it is one of the most striking features on the land surface of that part of the country. Although sheet erosion is significant, one usually thinks of gullying whenever soil erosion is mentioned in the area. This is mainly because erosion features, mostly the gullies constitute an interesting form of topography and are also a source of great concern, especially in terms of their adverse effect on the agricultural potentialities of the area. The major concern of this paper is to review some of the existing measures against soil erosion especially in their inadequacy and attempt to consider some appropriate management strategies. Before doing this, however, it would be necessary to outline briefly the factors, types, extent and process of soil erosion in Southeastern Nigeria.

(2.) Poesen, J., 1988. A Review of the Studies On The Mechanisms Of Incipient Rilling And Gullying In The Belgian Loam Region, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/034, volume 1(1);p.13-20.

A REVIEW OF THE STUDIES ON THE MECHANISMS OF INCIPIENT RILLING AND GULLYING IN THE BELGIAN LOAM REGION

J. POESEN

Research Associate, National Fund for Scientific Research, Laboratory of Experimental Geomorphology, K.U. Leuven, Redingenstraat 16 bis, B-3000 Leuven, Belgium

 

ABSTRACT

Rill and gully erosion account for 60 to 80% of total sediment produced in the Belgian Loam Region. A summary of recent research results obtained at the Laboratory of Experimental Geomorphology is presented, elucidating some factors controlling rill and gully formation. Conditions for rill genesis can be described by the ratio between overland flow, shear stresses and topsoil shear strength. The influences of soil shear strength, soil texture and soil water content on these conditions are discussed. Finally, the role of the biological factor in both rill and gully formation is described.

(3.) Egboka, B.C.E., 1988. Erosion Hazards In Southeastern Nigeria: Hydrological and Environmental Implications and Suggested Control Programmes, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/003, volume 1(1);p.21-22.

EROSION HAZARDS IN SOUTHEASTERN NIGERIA: HYDROLOGICAL AND ENVIRONMENTAL IMPLICATIONS AND SUGGESTED CONTROL PROGRAMMES

B.C.E. Egboka

Special Project/Research Unit Anambra State University of Technology, Awka Campus, P.M.B 5025, Awka, Nigeria.

ABSTRACT

Parts of Southeastern Nigeria (Benue, Anambra, Imo, Akwa-Ibom and Cross River States) are ravaged by soil and gully erosion and landslides. Lives and property have been lost. The genesis of the hazards is rooted in the environmental factors of rainfall, geomorphic and pedologic features, the peculiar nature of the north-south trending escarpments, geological, geotechnical and hydrogeological characteristics, and anthropogenic activities. The erosional processes are complex, dynamic, continuous and regional in nature, making control programmes difficult and unsuccessful. This is further complicated by erosional problems and dynamics being poorly-understood. Experts from different disciplines involved in erosion investigations and control misunderstand themselves. Geologists, pedologists, agriculturists, foresters, engineers, differ widely in suggestions proffered. This has exacerbated erosion problems. Sheet, rill, channel/bank and gully erosion and landslides in Southeastern Nigeria demand a multidisciplinary, multi-objective, multi-technique and integrated approach in both investigations and control. The Local, State and Federal Governments and higher institutions must be involved in coordinated efforts to combat these endemic hazards. An Environmental Hazard Monitoring Centre (EHMC) for southeastern Nigeria must be established. The EHMC shall monitor the quasi-stable environment on a continuous basis in order to predict potential hazards and suggest urgent contingency measures.

(4.) O. Aneke., 1988. Case Studies Of Erosion Control Projects In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th April., 1988, Paper ISE/SEN/002, volume 1(1);p.22-23.

CASE STUDIES OF EROSION CONTROL PROJECTS IN SOUTHEASTERN NIGERIA

D.O. ANEKE

Department of Agricultural Engineering, University of Jos, Makurdi Campus, Makurdi

 

ABSTRACT

The history and factors of gully erosion control in Southeastern Nigeria are briefly stated. Case studies of erosion projects in the region is the main topic discussed. Although natural forces cause erosion, the single most important agent of erosion is man. This takes place when he carelessly inflicts his activities on land. Consequently, expensive corrective measures have to be taken to safeguard life and property. Appropriate corrective measures cannot be effectively adopted if the hydraulic processes and the underlying science of erosion is not well understood. Such corrective measures and the hydraulic processes of erosion phenomenon are therefore discussed in this paper. The highlights of this paper are the new dimensions in soil erosion phenomenon and the recommendations for effective control programme in the states.

(5.) Boers, T.M., H.O. Maduakor and D.P Tee., 1988. Sheet Erosion From A Bare Sandy Soil In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/024, volume 1(1);p.23-34.

SHEET EROSION FROM A BARA SANDY SOIL IN SOUTHEASTERN NIGERIA

BOERS, T.M., H.O. MADUAKOR AND D.P. TEE

Federal University of Technology Owerri, Nigeria

ABSTRACT

The changes in water and soil balances caused by the removal of a tropical rain forest, which exposes the soil to erosive rainfall are discussed in this paper. Sheet erosion from bare soil was measured on runoff plots of 22 x 4m2 each, located on a slope of loamy sand. Three surface treatments were investigated: bare smooth soil without ridges, bare soil with ridges down the slope and bare soil will contour ridges. The effect of raindrop impact on bare soil was evaluated. Measurements of dry bulk density and infiltration rate were taken to estimate topsoil compaction and crust formation during the rainy season of 1987. Measurement of rainfall, runoff and soil loss indicates a very high erosion intensity in tons of soil loss per ha per year. Infiltration rates measured with the double ring infilterometer are discussed, and it is concluded that these measurements are not relevant for erosion research. An alternative method to evaluate infiltration rates from rainfall-runoff events is considered and applied.

(6.) Nwachukwu, B.A., 1988. Regime Dimensions Of Natural Streams In Imo State, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/025, volume 1(1);p.35-41.

REGIME DIMENSIONS ON NATURAL STREAMS IN IMO STATE, NIGERIA

B.A. NWACHUKWU

School of Engineering,  Federal University of Technology, Owerri.

ABSTRACT

Channels formed in alluvial or other granular materials are said to be in-regime if their geometry remains substantially unchanged by scour or sediment deposition. This, however, does not preclude minor channel erosion or accretion during yearly cycle of flow but it does require that opposing effects should cancel out on an annual basis. The regime concept was initially formulated on the experience gained from canal systems but since the concept is based on the theory of channel self-adjustment, it has been found applicable both for unlined canals and natural streams. It is now accepted practice to design stable canal systems from a set of regime equations determined from natural streams in the locality of the work. In this paper, a set of regime equations determined from a survey of natural streams in Imo State is presented. The equations are compared with the regime equations developed for some other countries. It is found that the present set of equations conform to those other equations with some difference only in the coefficients. The new set of equations is proposed for the design of non-erodible channels in Imo State and it is suggested that the study be extended to other states in South-Eastern Nigeria to determine if the equations are consistent for this larger geographical area.

(7.) Ezeigbo, H.I., 1988. Erosion And Gullying Problems In Umuahia And Environs, Imo State, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/023, volume 1(1);p.41-42.

EROSION AND GULLYING PROBLEMS IN UMUAHIA AND ENVIRONS

H.I. EZEIGBO

Department of Geology University of  Nigeria, Nsukka.

ABSTRACT

Field studies of erosion and gullying sites in Umuahia and environs were carried out in over 200km2 of territory. The affected geological formations are mainly the Ameki Formation and the Ogwashi-Asaba Formation even though some significant gullying occurs within the younger Benin Formation outcrops to the south. Within the Umuahia urban, poorly constructed and/or inadequate drainage channels expose the loose soils to erosion and gullying by the usually intense rains of the area. Within rural areas, deforestation is a major causative factor. The densely populated rural areas rely mainly on wood for energy, and bush burning remains a favoured agricultural practice. Little or no consideration is made for drainage channels in the “development” roads build in the rural areas. Both the Ogwashi-Asaba and Benin Formations have clay intercalations that furnish easy sliding surfaces when wetted by infiltrating rainwater. Several measures have been recommended for controlling the gullying menace which includes water channelization efforts, planned agricultural practices, public education on alternative energy sources as well as some legislation.

(8.) Sluiter, – W.J., 1988. Some Geomorphological Factors and Their Influence On Erosion in the Osina Basin , Southeastern, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/027, volume 1(1);p.43-46.

SOME GEOMORPHOLOGICAL FACTORS AND THEIR INFLUENCE ON EROSION IN THE OSINA BASIN, SOUTHEASTERN NIGERIA

W.J. SLUITER

Federal University of Technology,  Owerri.

ABSTRACT

The present study, executed in a part of the Imo river basin, Nigeria, shows the possibility of making a slope map and a surface run-off map utilizing a topographic map. The slope, as well as the surface run-off, has a direct relation to erosion intensity.   The above-mentioned maps have been prepared as a contribution to the compilation of an erosion hazard map, an essential tool for the control of erosion in the Imo River Basin.

(9.) Eppink, L.A.A.J.,1988. Research On Modern Survey Methods In Erosion Project Studies, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/027, volume 1(1);p.47-53.

RESEARCH ON MODERN SURVEY METHODS IN EROSION PROJECT STUDIES 

(A review of an Erosion Research Programme of the Wageningen Agriculture University)

EPINK, L.A.A.J.

ABSTRACT

At the Agricultural University at Wageningen, several Departments provide for teaching and research on soil erosion. Integration of the different aspects is obtained in Erosion Study Projects which are carried out in Spain. The overall goal is the formulation, elaboration and evaluation of alternative soil and water conservation plans for a specific watershed or sub-watershed, which are technically effective, economically feasible and socially acceptable. During the planning process, much information, obtained from maps, documents, photogrammetry, air photo-interpretation, field observations, measurements and inquires have to be used in different combinations. In order to study the possibilities of the use of advanced survey methods in the field, a methodological study is being carried out. Because such a study needs a continuous checking of partial results with field conditions, a small pilot area near Wageningen has been selected. Simultaneously, two other projects are going on. In cooperation with the University of Utrecht, a small watershed near Clatsop in the hilly southern part of the Netherlands is being surveyed and monitored and the ANSWERS simulation model is being tested out. Some results will be presented. Another project study in Spain serves as a teaching project for our students. In that project, the findings of the former programmes are tested on practical applicability.

(10.) Ijioma, C.I., 1988. Compactive Energy For Erosion Control On Earth fill Materials At Ohafia, Imo State Of Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/032, volume 1(1);p.54-58.

COMPACTIVE ENERGY FOR EROSION CONTROL ON EARTHFILL MATERIALS AT OHAFIA,

IMO STATE OF NIGERIA

C.I. IJIOMA

School of Engineering and Engineering Technology, Federal University of Technology Owerri.

ABSTRACT

Some serious soil erosion sites in Imo State have been associated with the disturbance of soil during and after major civil engineering works. Some of these works include: land grading, urban roads, dams and inter-city roads, all of which involve compaction to maximum density. Unfortunately, the compactive energies employed to achieve a certain maximum dry density have never been related to the resulting dispersive characteristics of the disturbed compacted soil. The erodibility of these earth fill materials has adversely given rise to different forms of erosion. A method is being developed to relate the compactive energies into the electrical conductance of the water passing through a pin hole in a compacted lateritic soil. The test has been carried out on soil samples from Ohafia in Imo State.

(11.) Chukwueze, H.O., 1988. The Contributions Of Soil Erosion To Pavement Failures In Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/032, volume 1(1);p.59.

THE CONTRIBUTIONS OF SOIL EROSION TO PAVEMENT FAILURES IN NIGERIA

H.O. CHUKWUEZE

Department of Civil Engineering, University of Nigeria, Nsukka.

 ABSTRACT

The paper examines the role of soil erosion in the progressive destruction of many paved roads in Anambra State and suggests how the phenomenon may be checked. Some fieldwork was conducted which revealed that the failure of the road pavement may start from the road shoulder which is composed of uncompacted materials usually sand with clay. The removal of the shoulder materials exposes the pavement structure which is usually stratified and so is selectively eroded thereby destabilizing the superjacent layers which then cave in. The destruction of the pavement at the culverts begins with the understand-scouring of the culvert chamber composed of units of segmented concrete casts. The units break off at the joints under the resultant moments. In either of the two cases observed, the road pavement fails in a progressive manner as the erosion element eats its way across the pavement structure. It is shown that the removal of the road pavement shoulder materials by the flowing rainwater may be minimized if carefully blended well-graded sand-gravel mixture is used. Also, the collapse of the shoulder could be prevented at culverts if monolithically cast concrete culvert chamber rather than the segmented ones are used. The improved methods need not increase the initial costs and will certainly reduce the maintenance costs of the pavement. These measures added with expert advice especially of the soil engineers should reduce or stop the phenomenon.

(12.) Posen, J., 1988. Surface Seal Formation And Soil Erosion Sub-processes, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/004, volume 1(1); p.60-67.

SURFACE SEAL FORMATION AND SOIL EROSION SUB-PROCESSES

J. POSEN

Research Associate, National Fund for Scientific Research, laboratory of Experimental Geomorphology, K.U. Leuven, Redingenstraat 16 bis, B -3000 Leuven, Belgium.

ABSTRACT

Surface sealing is an important process of physical soil degradation in Southeastern Nigeria. Therefore, a summary of recent research results obtained at the Laboratory of Experimental Geomorphology is presented in order to elucidate some factors controlling seal formation as well as the interactions between surface sealing and soil erosion sub-processes. Sandy soils containing 80 to 95% sand and 20 to 5% silt and/or clay have been found to be extremely susceptible to surface sealing. Topographic parameters such as slope gradient and length have a negative effect on sealing intensity. This is explained by the fact that the erosion rate largely controls seal development. On the other hand, surface seal formation determines in an ambivalent way, the rate at which several soil erosion sub-processes by water operate: surface sealing decreases the intensity of inter-rill erosion subprocesses but increases the runoff volume and hence, the potential for rill and gully erosion.

(13.) Chukwuma, G.O., 1988. The Effects Of Bamboo Roots In Gully Slope Stabilization, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/004, volume 1(1); p. 68.

THE EFFECTS OF BAMBOO ROOTS IN GULLY SLOPE STABILIZATION

G.O. CHUWKUMA

Department of Agricultural Engineering, University of Nigeria, Nsukka.

ABSTRACT

Bamboo (Bambusa vulgaris) is widely used in gully slope stabilization but there is no documented evidence of the effectiveness of bamboo roots in reinforcing the soil mass against shear failure. The study explores the engineering properties of soil samples taken from beside a bamboo stand used in gully erosion control and compares the result with those obtained from soil samples taken at distance from the bamboo stand but within the same soil type. The results of the study will be useful in developing a technical guide for recommending bamboo as a vegetative soil erosion control measure for varying gully slopes.

(14.) Okeke, P.O., G.I, Nwankwor and G.N Nnadi .,1988. Development Of A Model For Gully Erosion For S.E Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/029, volume 1(1); p.69.

DEVELOPMENT OF A MODEL FOR GULLY EROSION FOR SOUTHEASTERN NIGERIA,

P.O. OKEKE, G.I., NWANKWOR AND G.N. NNADI

Federal University of Technology, Owerri.

ABSTRACT

Erosion studies of south-eastern Nigeria are being implemented under the EEC/FUT, Owerri Linkage. One of the sub-themes of these studies is the development of a model for gully erosion for south-eastern Nigeria. The authors of this report are members of this sub-theme. The phase 1 of the sub-theme involves the determination of the geometric characteristics, such as the thickness of erodable materials and the real extent of the watershed using either seismic survey or vertical Electrical Soundings (VES) over selected areas within south-eastern Nigeria. It is possible that through these geophysical investigations (depending on the penetration or probe depth), geologic discontinuities – cavities, joints, fractures and faults which cause gully erosion will be mapped. Although these discontinuities are not explicitly represented in the model equation, any knowledge about their presence will influence the evaluation of model behaviour. Three sites which have been known to be classic ongoing erosion sites in southeastern Nigeria – Okwudo, Amucha and Osina were chosen for the Phase 1 investigation. The Federal Surveys map of Nigeria of 1967 (sheet 312-Okigwe), clearly shows the nature of gullies in these sites.  Four soundings were done, using the Schlumberger configuration.  All results were interpreted with an IBM Computer. All studies were done in March 1987.

(15.) Nwachukwu, B.A and C.I. Ijioma., 1988. Performance Evaluation Of Civil Engineering Structures For Erosion Control In Southeastern Nigeria: Case Study, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/021, volume 1(1);p.70-75.

PERFORMANCE EVALUATION OF CIVIL ENGINEERING STRUCTURES FOR EROSION CONTROL IN SOUTHEASTERN NIGERIA – CASE STUDY

B.A. NWACHUKWU AND C.I. IJIOMA

School of Engineering and Engineering Technology, Federal University of Technology, Owerri

ABSTRACT

Erosion control can be achieved by both structural and non-structural measures. In the main, the structural measures are applied to gully erosion and stream bank erosion; non-structural measures for erosion control are mostly applicable to sheet erosions. Gully erosion is mostly as a result of flow concentration from civil engineering works or drainage basin modification, and bank erosion results from high stream velocities. The objectives of the research team centred on the appraisal of the performance of in-place structures used to prevent gully and stream bank erosions in selected locations in Southeastern Nigeria. The studies so far completed included the bank erosion of  Ekuku River near Enugu Airport in Anambra  State and the geotechnical investigation of the gully erosion control works in Abiriba and Ohafia in Arochukwu/Ohafia Local Government Area in Imo State.

(16.) Tee, D.P., 1988. Groundwater, Surface Runoff and Erosion: How Related?, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/010, volume 1(1); p.76-81.

GROUNDWATER, SURFACE RUNOFF AND EROSION: HOW RELATED?

D.P. TEE

Department of Civil Engineering, Federal University of Technology Owerri.

ABSTRACT

The paper describes a study undertaken at Amucha, Imo State, one of the serious erosion sites in the Southeastern states of Nigeria. The study concentrates on the relationship between groundwater, surface runoff and erosion. Field observation and various measurements strongly confirm that soil erosion results from a combination of various forces including groundwater. Groundwater extruding through various weak points along the stream channel downslope results in undercuts causes a reduction in granular pressure and provides for increased erodibility by surface runoff. The stream channel was seen as a groundwater drain or a point of discharge for excess groundwater from infiltrated rainwater. The study revealed that the excess of the initially low groundwater discharge capacity by precipitation surplus resulted in an enlargement of the groundwater discharge area and that upward seepage and outflowing of groundwater weakened the cohesive force of the soil thereby encouraging the sliding of the overburden materials.

(17.) Ibe, K.M., S.E. Ananaba,, W.J. Sluiter., H. Krynen and B. Nwachuwku., 1988. Sampling Of Geology and Hydrology Of Chosen Sites In The Study Area – A Progress Report, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/019, volume 1(1);p.82.
(18.) Boer, T.M., H.O. Maduakor and D.P. Tee., 1988. Measurements Of Rainfall, Runoff And Soil Loss On Experimental Plots For Development Of A Sheet Erosion Model, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/018, volume 1(1); p.83.

MEASUREMENT OF RAINFALL, RUNOFF AND SOIL LOSS ON EXPERIMENTAL PLOTS FOR DEVELOPMENT OF A SHEET EROSION MODEL

BOER, T.M.,  H.O. MADUAKOR AND D.P. TEE

Federal University of Technology,  Owerri.

ABSTRACT

This paper reports on progress made in subtheme number 3 of the EEC Erosion Research Project during the period April  1986  to  April 1988. The data obtained during the year 1987 are suitable for the use of a simple hydrological model based on daily measurements of rainfall, runoff and soil loss. Continued measurements, which should include accurate hydrogen recording, will allow the development of a more advanced model based on the kinematic wave equation. The paper discusses experimental work completed on 6 runoff plots with 3 different surface treatments: smooth surface no ridges, ridges down the slope and ridges across the slope. All details regarding materials and methods, collected data and discussion of results are reported in a technical paper written for the International Symposium on Soil Erosion in South-Eastern Nigeria. Some problems encountered in the research are discussed and the paper further outlines future directions for research followed by concluding remarks.

(19.) Nwachukwu, B.A and A.J.C. Van De Kerk., 1988. Estimates of Drainage Basin Erosion Index From Stream Sediment Load Measurements, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th , 1988, Paper ISE/SEN/009, volume 1(1);p.84-90.

ESTIMATES OF DRAINAGE BASIN EROSION INDEX FROM STREAM SEDIMENT LOAD MEASUREMENTS

B.A. NWACHUKWU AND A.J.C. VAN DE KERK

Federal University of Technology, Owerri.

ABSTRACT

Soil loss or erosion in a drainage basin is affected by the processes of particle detachment by raindrops, entrainment at a competent velocity of the surface runoff and sediment transport. The transported materials may be carried into the stream channel where it moves thereafter with the stream-flow as either bed load, suspended load or wash load depending on the flow and particle characteristics. The amount or rate of erosion in the drainage basin may, therefore, be estimated from sediment transport measurements in the receiving stream and the accuracy of this estimate would depend on the delivery efficiency of sediment from the basin to the channel. In general however, the accuracy of the estimates would increase when averaged over a long period of measurements. In the study reported here, the erosion rates of two drainage basins in Imo State are determined from stream sediment transport measurements. To obtain the estimates, water level recorders were installed in the streams and rating curves were established by discharge measurements at various stages. Also from simultaneous measurements of discharge and suspended sediment load, the sediment rating curves for the streams were equally established. The sediment yields of the basins were estimated by relating both the stage-discharge curve and the sediment rating curve with the stage hydrograph over the period of available data. The erosion rates for the two basins were estimated as 3600 and 23,100 tonnes per annum respectively. The factors responsible for the observed low rate of erosion for the two basins are discussed.

(20.) Krynen, H., 1988. A Study of Erosion (Cause and Remedies) Based On Hydrological Data, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/015, volume 1(1); p.91.

A STUDY OF EROSION (CAUSES AND REMEDIES) BASED ON HYDROLOGICAL DATA

KRYNEN, H.

Federal University of Technology, Owerri.

ABSTRACT

The study is based on data collected in subtheme 4 concerning hydrology. Furthermore, data were obtained from the meteorological service, from Imo River Basin Authority and Techno Synesis. After an introduction and description of the different forms of erosion,  the paper concentrates on hydrological analysis. The analysis consists of rainfall analysis – infiltration analysis- determination of runoff and sediment yield. The risqué of erosion and the control measures are related to the slopes and land-use. Therefore the first approach to erosion must be correct land-use based on land classification. Basically there are two types of mechanical protection works. Drainage and storage realization of a drainage system will be very costly and therefore temporary storage is preferred. For farmland in flat areas, hardly any measures are needed. For farmland on slopes, temporary storage can be affected by applying tillage with ridges within contour bunds. Along roads, infiltration pits should be constructed and in areas, with houses, the solution to avoid runoff will be water harvesting.

(21.) Ijioma, M.A., 1988. A Conceptual Ecosystems Model For Effective Gully Erosion Management: A Case Study Of Onu Igbere Gully, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/031, volume 1(1);p.92-97.

A CONCEPTUAL ECOSYSTEMS MODEL FOR EFFECTIVE GULLY EROSION MANAGEMENT:

A CASE STUDY OF ONU IGBERE GULLY

M.A. IJIOMA

School of Environmental Studies, College of  Engineering and Environmental Studies, Imo State University, Okigwe.

ABSTRACT

Gully erosion is a characteristic feature on the soft sediments of the gently exposed plains, characterized by semi-consolidated soils, found widely in various parts of the Eastern States. Over this region, the total annual rainfall is high and the intensity is also high. The gully site at Onu Igbere in Bende L.G.A (Imo State) is used as a case study to describe the morpho-dynamic processes influencing gully formation in development in an erosion system to bring to sharper focus gully development in any endangered watershed. Most importantly, the present paper validates the application of a conceptual ecosystems model in ensuring an effective gully erosion control in any watershed in Nigeria in general and in the Eastern States in particular. The ecosystems model proposed here has two main stages – the planning and design stage and the implementation and evaluation stage. The elements in the model include the energy flow transformation, the purpose for such transformation, the design to be undertaken, the professional expertise needed, the academic disciplines involved and the expected results.

(22.) Nwankwor, , G.I. ,P.O. Okeke And E. Castenmilla., 1988. Determination And Relevance Of Parameters Of A Gully Growth Model For Okwudor – Amucha Gully Complex, Imo State, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/033, volume 1(1); p.98.

DETERMINATION AND RELEVENACE OF PARAMETERS OF A GULLY GROWTH MODEL FOR OKWUDOR – AMUCHA GULLY COMPLEX, IMO STATE, NIGERIA

G.I. NWANKWOR, P.O. OKEKE AND E. CASTENMILLA

Department of Geology, Federal University of Technology Owerri.

 

ABSTRACT

The governing principles of a model that can be used to predict gully growth and appraise the effectiveness of various control schemes in the Amucha-Okwudor gully are posed. The envisaged model is based on a relationship between a dependent variable (gully growth rate) and a set of independent variables (factors affecting this growth). Five independent variables are considered and include soil strength (measured as clay content), rainfall, slope, watershed geometry and thickness of erodible material. The measured clay content of server soil samples in the study area range from 0.02% to 1.8%.The samples have porosity values of between 0.3 and 0.47, and an average void ratio of 0.6. The thickness of the erodible material was estimated as 30m using geophysical methods. The slope of the approach channels ranges from about 80 near the uplands to over 300 near the valley walls. Other factors that affect soil strength such as groundwater seepage forces were also investigated. Preliminary calculations that were made using realistic rainfall values and representative values of the other independent variables yielded an average lateral gully growth rate of about 25m/yr. This rate is comparable to those that have need measured for other gullies thus probably suggesting the appropriateness of the proposed model.

(23.) Boers, T.M., U. G. Atu., J.C. Obifuna and D.P . Tee., 1988. Aspects Of Ridging And Cropping For Gully Reclamation, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/016, volume 1(1); p.99.

ASPECTS OF RIDGING AND CROPPING FOR GULLY RECLAMATION

BOERS, T.M.,  U.G. ATU.,  J.C. OBIFUNA AND D.P. TEE

Federal University of Technology, Owerri, Nigeria

ABSTRACT

This paper reports on progress made in subtheme 1 of the EEC Erosion Research Project during the period August 1986 to April 1988. The history of a gully which developed in a slope at the campus of the Federal University of Technology Owerri is briefly discussed. Civil engineering measures were taken to cut off the upstream catchment area, close the gully with bulldozers and construct contour bunds to divide the slope into sections. Subsequent agricultural development of the area had not been completed which continued the threat of renewed gully formation. An experimental field was established on the 2 ha slope where field trials were set up of ridging and cropping to develop proper methods to complete the gully reclamation process. The paper specifies selected cropping patterns for different sections of the field and problems encountered in the research are discussed. Future directions for research are outlined and some concluding remarks and recommendations are made.

(24.) Maduakor, H.D., D.P. Tee., K.M. Ibe and C.I. Ijioma., 1988. Determination Of Erosion Related Parameters At Chosen Sites, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/017, volume 1(1); p.100.
(25.) Olaniyan, G.O., 1988. Assessment Of Soil Erosion Under Different Seed Bed Preparation In South East Nigeria , Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/007, volume 1(1); p.101.

ASSESSMENT OF SOIL EROSION UNDER DIFFERENT SEED BED PREPARATION IN SOUTHEAST NIGERIA

OLANIYAN, G.O

NCRI, Badeggi

ABSTRACT

Under clean clearing and land preparation, the land is exposed for some time after sowing before crop vegetation cover. It is during this period that soil erosion is rapid under the humid climate. Therefore, this paper presents the report of work carried out in Southeastern Nigeria on soil erosion under different cultivation methods. The experiment was sited at Amakama, near Umuahia (Lat. 5.50 N, Long. 7.50 E) in the lowland rain forest zone. The area was manually cleared from the secondary forest and put under cultivation in 1977 using different tillage methods of burn and plough; no burn and plough; burn and no-plough and no-burn and no plough laid out in a randomized block design with three replications. Plot size was 10 x 20m, and in 1983, runoff plots of 1m x 1m were installed in all the treatments. Eroded soil and runoff were channelled into calibrated collecting bucket provided at the lower end of each runoff plot. Each morning after it had rained the previous day, the volume of eroded soil plus run-off was read on the calibrated wall of each bucket and the water drained off allowing the sludge to settle out. The sludge was then transferred into a drying tray, dried in the oven and weighed. From twelve days after planting, soil loss was significantly higher in all ploughed plots (burning 1.92t/ha; no burn 1.79t/ha) than in no-tillage plots of burn at 1.45t/ha and no burn at 1.28t/ha. It was also noticed that between six and eight weeks after planting, at about the time of second weeding and immediately after weeding, soil erosion was again significantly higher under all the ploughed treatments. The implication of these findings for soil and crop management in the region is discussed.

(26.) Maduakor, H.O., 1988. Soil Physical and Chemical Properties Affecting Erodibility of Some Soils In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/008, volume 1(1); p.102-106.

SOIL PHYSICAL AND CHEMICAL PROPERTIES AFFECTING ERODIBILITY OF SOME SOILS IN SOUTHEASTERN NIGERIA

H.O. MADUKAOR

School of Agric and Agricultural Technology,  Federal University of Technology Owerri.

ABSTRACT

Some physical and chemical properties of soils collected from 2 transects in Southeastern Nigeria were correlated with the index of erodibility which in this study is the member of water drops (DRP) that shattered soil aggregates within 2 – 3 gm range. The index correlated positively with depth (D), bulk density (BD), fine sand (FS), clay (CL), organic carbon (OC), crystalline iron oxide (Fe l), amorphous iron oxide (Fe 2), amorphous aluminium oxide (A1 2 ) and crystalline aluminium oxide (All). It correlated negatively with coarse sand (CS), penetrometer resistance (PR) and pH. The regression equation determined using the step-down method of selecting the relevant variables is given as DRP = 52.82 + 9.13  AL 2  +  18. 16 BD- 0.18 D – 99.97 Fe 2 + 2.67 PR + 7.52 Fe 1 – 0.84CS; Where DRP, AL 2, BD, D, Fe2, PR, Fe 1, and CS are as explained above.

(27.) Obiefuna, J.C.,1988. Alterative Land Preparation Techniques as Anti-Erosion Management Strategy For Plantation Agriculture in the Tropical Rainforest, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/005, volume 1(1); p.107.

ALTERATIVE LAND PREPARATION TECHNIQUES AS ANTI-EROSION MANAGEMENT STRATEGY FOR PLANTATION AGRICULTURE IN THE TROPICAL RAINFOREST.

J.C. OBIEFUNA

School of Agriculture and Agricultural Technology,  Federal University of Technology, P.M.B 1526, Owerri Nigeria.

ABSTRACT

The experiment investigated the effect of alternative land preparation techniques on the development of sheet and gully erosion on a newly established citrus orchard in the tropical rainforest of Western Nigeria. The fields were 50m wide and 300m long on 12% slope. Land preparation included bulldoze, bulldoze + plough, bulldoze + plough + harrow, slash + fell, slash + fell + burn and slash + fell + burn + manual stumping . Graduated 50cm spikes were located at 20m intervals in each plot along the slope and monthly mean values calculated. Generally, sheet and gully erosion were highest in the upper and mid reaches of harrowed, ploughed bulldozed but least in unburnt fields. Once the gully erosion developed, initial lateral expansion was rapid but subsequently increased gradually by caving – in following progressive deepening and cutting back into the upper reaches of the developing gully. The total soil losses from the upper and mid reaches were apparently greater than sedimentation at the lower reaches. The implications of formulating anti-erosion measures prior to crop canopy cover in high rainfall areas were suggested.

(28.) Isirimah, N.O and L.C. Nwaigbo., 1988. Soil Erosion and Control Efforts In Some Parts Of Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/035, volume 1(1); p.108.

SOIL EROSION AND CONTROL EFFORTS IN SOME PARTS OF SOUTHEASTERN NIGERIA

ISIRIMAH, N.O AND L.C. NWAIGBO

Department of Crop/Soil Science and Forestry, River State University of Science and Technology, Port Harcourt.

ABSTRACT

Soil erosion causing factors and control measures in Southeastern Nigeria, dating back to 1982 were reviewed. Only eight out of the many identifiable serious gully erosion affected sites are described and assessed. Highway construction plus the fragile nature of the soils in the regions are known major causes for the serious gully erosion. Preservation of vegetation and forest cover remains the cheapest means of stabilizing eroded sites. This paper suggests an integrated approach to soil erosion control which should involve soil scientist, foresters, engineers and socio-economists. Erosion control work should be a continued programme rather than a crisis management measure usually taken for areas that are threatened.

(29.) Asiabaka, C.C and T.M. Boers. 1988. An Analysis Of The Existing Traditional Methods Of Farming And Erosion Control Among Farmers In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/036, volume 1(1); p.109-114.

AN ANALYSIS OF THE EXISTING TRADITIONAL METHODS OF FARMING AND EROSION CONTROL AMONG FARMERS IN SOUTHEASTERN  NIGERIA

ASIABAKA, C.C

School of Agriculture and Agricultural Technology,  Federal University of Technology, Owerri Nigeria.

AND

T. M. BOERS.

Wageningen Agricultural University, the Netherlands.

 

ABSTRACT

The major objective of the study was to determine the existing traditional methods of farming and erosion control in selected areas of S.E. Nigeria. Six communities: Okwudor, Amucha, Amaigbo, Isiekenesi, Ihitenansa and Obibi-Ochasi were selected because they were heavily affected by gully erosion. From these communities, a random sample of 130 farmers was selected and given instruments to complete. This survey instrument asked questions relating to their socio-economic status, problems confronting them, methods of planting and their traditional methods of erosion control. The results showed that about 28% of the farmers did not attend school at all. Only 13% completed secondary education. Findings also show, that most farmers planted on mounds and beds. Only very few planted on ridges. The traditional methods of erosion control used by farmers were mixed cropping, shifting cultivation, three plantings (bamboo) and digging crossbars. The farmers in the study perceived declining yields, destruction of farmland and houses as the most serious problems of erosion. Data analysis revealed that the most appropriate method of dissemination of erosion control information is through the extension agents. Other methods included radio, other farmers, television and film shows. Most farmers (68%) felt that government action is the major solution to the erosion menace.

(30.) Njoku, J.E And C.C Asiabaka., 1988. Government Policies And Programmes On Erosion Control In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/037, volume 1(1); p.115.

GOVERNMENT POLICIES AND PROGRAMMES ON EROSION CONTROL IN SOUTHEASTERN NIGERIA

NJOKU, J.E  AND C.C ASIABAKA

School of Agriculture and Agricultural Technology, Federal University of Technology, Owerri.

ABSTRACT

This paper attempts an analysis of government policies and programmes on erosion control in the four Southeastern States of Imo, Anambra, Rivers and Cross River States of Nigeria. It points out the constraints to erosion control and provides suggestions for enhancing government efforts toward erosion control. The data used for analysis were collected through questionnaire interviews of heads of government ministries and Parastatals involved in erosion control in each of four Southeastern States. The results indicate that there is a lack of comprehensive policies and programmes on erosion control. Finance is one of the major constraints of policy and programmes implementation. Formulation of more articulate and properly co-ordinated policies and programmes on erosion as well as an increased level of funding are suggested.

(31.) Abarikwu, O.I., 1988. The Challenges Of Erosion In Imo State, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/011, volume 1(1); p.116-119.

THE CHALLENGES OF EROSION IN IMO STATE

ABARIKWU, O.I.

Ministry of Agriculture and Natural Resources, Engineering Division, Owerri.

ABSTRACT

Soil erosion in Imo State has assumed disastrous proportions over the past few decades. From a few observations on the land use in the late ’60s and ’70s, the problem of soil erosion seems to have taken Imo State in a storm, and has now affected all parts of the State either in the form of gully or sheet erosion. Factors that are responsible for soil erosion in the state, as well as various remediation strategies, were discussed.

(32.) Okamigbo, F.O.R., 1988. Erosion Menace In Anambra State: Government Efforts In Combating It, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/012, volume 1(1); p.120-129.

EROSION MENACE IN ANAMBRA STATE: GOVERNMENT EFFORTS IN COMBATING IT

OKAMIGBO, F.O.R.

Chairman, Anambra State Task Force on Soil Erosion Control,

 Department of Soil Science, University of Nigeria, Nsukka, Nigeria.

 

ABSTRACT

Soil erosion is defined as a systematic removal of soil, including plant nutrients, from the land surface by the various agents of denudation. Soil erosion occurs in several parts of Nigeria under different geological, climatic and soil conditions. Causative agents include wind, rainwater, river water or sea waves, population density and anthropogenic activities. Causative agents prevalent in Anambra State are elucidated. The story of soil erosion particularly in Anambra State was traced as far back as 1922 when the first recorded effort at biological control was made. The efforts of the Government of Anambra State to combat the menace are discussed. The special efforts of the Task Force on Soil Erosion Control in Anambra State are elaborated. The census and identification of gully sites conducted in 1987 showed that over 530 gully complexes are ravaging the state. The probable reasons for this high incidence were adduced. The landmass lost to the gullies was estimated at 176,750 hectares, approximating 10% of the total land area of the State. Other losses included over 150 lives, many livestock and civil infrastructure. The value of a property and landmass so far lost to gully erosion was estimated at 5.3 billion naira (about 1.4 billion U.S. dollars).  Strategies for combating the menace was proposed. They are two main approaches, engineering curative and biological/minor engineering measures, all based on proper watershed protection and management. A call for assistance was made in order that the state did not break up into pieces of badly eroded “islands”.

(33.) Etukudo, I.E., 1988. Soil Erosion Control: A Case Study In Akwa Ibom State, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/012, volume 1(1); p.130-141.

SOIL EROSION CONTROL: A CASE STUDY IN AKWA IBOM STATE

ETUKUDO, I.E.

Ministry of Agriculture and Natural Resources, Forestry Division Headquarters Uyo, Akwa Ibom State.

ABSTRACT

The location of Akwa Ibom State within the Rain Forest Belt of Nigeria, in addition to having the Atlantic Ocean as its Southern boundary, makes the problem of erosion in the state a peculiar one. The causes and types of soil erosion in the state are reviewed. The major erosion affected sites in each of the 10 (ten) Local Government Areas are listed. Control measures appropriate to the peculiar erosion problems of the state are examined in conjunction with the various agencies which participate in erosion control. Details are given of the measures applied to control erosion in selected areas of the state where the threat by erosion had reached alarming proportions. The part played by the Forestry Service in applying the biological control measures is emphasized. The constraints militating against the rapid and effective application of control measures are highlighted and suggestions advanced for the future.

(34.) Njoku, J.E., C.C. Asibaka, J.C. Obiefuna., 1988. Soico-economic Impact of Soil Erosion In The Oil Palm Belt Of Southeastern, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/022, volume 1(1); p.142.
(35.) Okorie, P.E., C.C Ibe and K.C. Akudike, 1988. An Appraisal Of The Vegetation In Onicha and Ahiazu Mbaise Gullies, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/006, volume 1(1); p.143.

AN APPRAISAL OF THE VEGETATION IN ONICHA AND MBAISE GULLIES, IMO STATE

OKORIE, P.E., C.C. IBE AND K.C. AKUDIKE

Forestry Research Institute of Nigeria, P.M.B. 5054 Ibadan

 

ABSTRACT

A survey of the vegetation in two gullies in Ahiazu and Onicha Mbaise was carried out to determine species density and growth. Gmelina Arborea Roxb had been introduced in both sites and pines ( Pinus Caribaea Mor.) and bamboos (Bambusa vulgaris  Schard) in only the Ahiazu gully, three years before this sample plots were randomly laid out on hilltop, slope and valley portions of each gully and a hundred per cent enumeration of the species was taken. The lateral roots of 15 tallest trees (from 3 dominant species) were partially exposed, traced to their tip and their lengths measured. Heights, diameter at breast height(dbh) and crown diameters of the introduced exotics were also measured. The results showed that there were twice more indigenous plant species in Onicha than in Ahiazu gully. The most abundant species in Onicha gully were Acio bacteri, Daniellia ogea and Raphia hookeri constituting 22%, 10.1% and 9.2% respectively of the vegetation. Gmelina was the most abundant species in Ahiazu and comprised 27.4%, while Rahia hookeri and Acio bacteri constituted 25% and 20.5% respectively of the vegetation. Daniela ogea and Pentaclethra macrophylla had the longest lateral roots (6.0 m and5.2m respectively) and Gmelina Arborea had the greatest height and diameter growth while Bambusa vulgaris had the least. The use of indigenous plant species in soil erosion control is highlighted.

(36.) Ibe K.M., 1988. Deforestation – A Cause of The Ecological Disaster Of Soil Erosion In Imo State, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th April., 1988, Paper ISE/SEN/006, volume 1(1); p.143.

DEFORESTATION – A CAUSE OF THE ECOLOGICAL DISASTER OF SOIL EROSION IN IMO STATE.

K.M. IBE

School of Earth, Mineral and Natural Science, Federal University of Technology Owerri

ABSTRACT

Soil erosion is a natural process which has been in operation since the formation of the earth. Soil erosion includes both the processes of material acquisition or detachment and that of transportation of soil materials by the erosive agent of water, wind and ice.  The impact of the natural geologic erosion was not felt because of its slow rate of operation but of late man’s activity has accelerated the rate of operation of soil erosion to a level which demands huge financial resources in order control the spread of soil erosion. Geographically, Imo State lies between 4 45’ N and 6 15’ N latitudes and between 6 30’ E and 8 15’ E longitudes. This places Imo State in the tropical rain forest zone characterized by heavy rainfall and high temperature. The soils of Imo State are generally of the acid sands which have a high degree of erodibility. The Udi and the Awaka – Orlu escarpments are characterized by steep and unstable slopes. In addition to the above factors, Imo State has a high population density of about 450 persons per square kilometre. With the above factors, the stage is thus set for a high incidence of soil erosion in the state. The history of accelerated soil erosion in Imo State dates back to the late 1940 and early 1950.