Rural Water Access and Management Approaches in Southern Africa： Lessons from Namibia and South Africa

Water scarcity is a major problem for Namibia and South Africa as both countries are classified as ＂water stressed＂, based on their per capita water availability which is below the threshold of 1,000-1,666 ma-person^-1.year^-1. Water provision in both countries has traditionally relied on supply-side sources, and the potential for expansion is becoming dim, making efforts towards demand management approaches more feasible. Findings show that CBM （community based management） systems of water points offer an alternative in terms of ownership and self-reliance based on institutional arrangements at community level. However, the CBM system involves some forms of payment for water access, and affordability has become a main challenge, to the extent that some governments are considering the reintroduction of water subsidies for poor rural communities in the near future.

Soil fertility effect on water productivity of maize in the upper blue nile basin, Ethiopia

Maize (Zea mays) is among the major cereals grown in the high rainfall areas of the subSaharan Africa’s (SSA) such as the Ethiopian part of the Blue Nile basin. However, its productivity is severely constrained by poor soil, water and crop management practices. This study simulated the water productivity of the crop under varying soil fertility scenarios (poor, near optimal and none limiting) using hybrid seeds under rainfed conditions using the FAO AquaCrop model. The result indicated that grain yield of maize increased from 2.5 tons.ha–1 under poor to 6.4 and 9.2 tons.ha–1 with near optimal and non-limiting soil fertility conditions. Correspondingly, soil evaporation decreased from 446 mm to 285 and 204 mm, while transpiration increased from 146 to 268 and 355 mm. Consequently, grain water productivity was increased by 48% and 54%, respectively, with the near optimal and non-limiting soil fertility conditions. The water productivity gain mainly comes from reduced evaporation and increased transpiration without significantly affecting water left for downstream ecosystem services. This has a huge implication for a basin scale water management planning for various purposes.

An Assessment of Climate Change and Available Water Resources in the Lowveld Region, Swaziland

Long-term climatic data （maximum temperature, minimum temperature, rainfall and evaporation） for Big Bend in the Lowveld, a semi-arid region of Swaziland, were analysed for any changes or variations. Evaporation and rainfall data were analysed to assess water resources availability in the region. Analysis of the available data shows that there is no indication of decrease in rainfall with time, but the results show that there has been a steady increase in minimum temperatures over the last 25 years. The average effective water resources index, measured as the difference between mean annual rainfall and mean annual evaporation, for the region in the period from 1965 to 2001 was -1,500 mm. The large negative index implies low available water for the region, a situation that is likely to affect agricultural, hydropower and other water related development activities in the region. The negative effective water index implies deficits in the region＇s water resources which call for better management of the region＇s water resources. In the agriculture sector, this requires promoting technologies and practices that provide for water saving, improved water use performance and high water productivity. These include soil conservation tillage, wastewater reuse, runoff harvesting and soil fertility interventions through application of fertilizers, manures and mulches, and agronomic management. There is need for more analysis for the other regions in order to get a countrywide picture of the climate as well as water resources situations.

Hydrological Impact Assessment of Climate Change on Lake Tana’s Water Balance, Ethiopia

The aim of this study is to evaluate the hydrological impacts of climate change on the water balance of Lake Tana in Ethiopia. Impact assessments are by downscaled General Circulation Model (GCM) output and hydrological modeling. For A2 and B2 emission scenarios, precipitation, maximum and minimum temperature estimates from the HadCM3 GCM were used. GCM output was downscaled using the Statistical DownScaling Model (SDSM 4.2). Impact analyses were applied for three future time periods: early, mid and late 21st century. Over-lake evaporation is estimated by Hardgrave’s method, and over-lake precipitation is estimated by inverse distance weighing interpolation, whereas inflows from gauged and ungauged catchments are simulated by the HBV hydrological model. Findings indicate increases in maximum and minimum temperature on annual base for both emission scenarios. The projection of mean annual over lake precipitation for both A2 and B2 emission scenarios shows increasing pattern for 21st century in comparison to the baseline period. The increase of mean annual precipitation for A2 emission scenario is 9% (112 mm/year), 10% (125 mm/year) and 11% (137 mm/year) for the three future periods respectively. B2 emission scenario mean annual precipitation shows increase by 9% (111 mm/year), 10% (122 mm/year) and 10% (130 mm/year) respectively for the three future periods. Findings indicate consistent increases of lake storage for all three future periods for both A2 and B2 emission scenarios.

Analysis of Cropping Practices on Two Irrigated Perimeters of the Volta Blanche Basin with the Use of Shallow Groundwater

This study aims to analyze the development of small-scale irrigation using shallow groundwater in Nahouri province (south-central Burkina Faso). The methodological approach adopted was essentially based firstly on semi-structured surveys with producers who have adopted sump technology and the monitoring of groundwater level using the installed piezometers and secondly on geophysical prospection. Results obtained show that market gardening is mainly a family activity practiced on plots of 0.20 ha with a predominance of pepper cultivation occupying about 75% of cultivated areas. It was also highlighted that this agricultural activity faces several constraints that delay its development. These include: lack of water, land insecurity, small and fragmented farms and difficulty in selling products when they are put on local markets at the very same time as significant price drops. This problem is accentuated by the perishable nature of these market garden products. Despite these limiting factors, there is some satisfaction considering the income earned by farmers, most of whom are able to meet their primary needs. This work made it possible to conclude that even in zones which are not sedimentary formations, it is possible to mobilize groundwater, at a reasonable depth for agricultural purposes, without much effort to practice additional irrigation, knowing that evaporation carries harm to the use of dams.

Hydrochemistry as Indicator to Select the Suitable Locations for Water Storage in Tharthar Valley, Al-Jazira Area, Iraq

Four locations were chosen according to geomorphologic and engineering criterion to store the water on the midstream of Tharthar valley, water samples were collected from the four locations to evaluate the hydrochemical properties as indicator to select the more suitable location, these locations are Hatra, Abu-Hamam, Tlol Al-Baj and Al-Sukkariah from the north to the south respectively. Also, the groundwater samples were collected from two shallow wells on the banks. The samples were analyzed to determine the concentrations of most common anions and cations in the water Ca2+, Mg2+, Na+, K+, CO32-, HCO3-, Cl–, SO42+. Also, pH, EC and TDS were measured. The results reflect high variations in concentrations of the soluble materials, the concentrations of these components are highly increased in locations of Tlol Al-Baj and Al-Sukkariah in comparison with the locations of Hatra and Abu-Hamam. The variation in geology of the area along the valley was represented a main role on the quality of water. These results can help to select the suitable locations of small dam (dams) to store the water in the valley and prevent the problem of salinity. According to the results, the northern part of midstream (north of Abu-Hamam) is suitable for water storage and the dam construction. While the locations of the downstream enriched by local sources of salts.

Water Quality Assessment by Measuring and Using Landsat 7 ETM+ Images for the Current and Previous Trend Perspective: Lake Tana Ethiopia

Recently there are signs of water quality impairment in Lake Tana, the largest fresh water in Ethiopia. The lake is the growth corridor of the government and supports millions of livelihood around. In order to sustain the benefit and maintain the ecosystem of the lake, the lake health has to be kept safe. Therefore monitoring and evaluation of the water quality of lake is very vital. This study focuses on current and previous trends water quality of the lake through measurements and Landsat Images near entry of Gumera River. Statistical analysis of the physical (Turbidity and STD and biological (Cha-a,) and chemical (DPC) water quality parameters were done. Linear and non-linear regression models between water quality parameter and reflectance of Landsat 7 ETM+ images were fitted based on band combinations. Pervious trend in turbidity was analyzed based on the regression models. The results showed that reflectance and turbidity satisfactorily result with an R2 ranging from 0.61 - 0.68. Form 1999-2014 the turbidity of the lake has indicated an increasing trend. Delta development near the entry of Gumera River has been enlarged by 48% because of an increase sediment inflow. The sign in the decreasing water quality of the lake was attributed to the non-point source sediment and nutrient inflow to the lake with high erosion rate from the watersheds. Measures to reduce the non-point source sediment and nutrient inflow by targeting the source areas (hot spots) in the agricultural watersheds need to be priority for stakeholders working on the soil and water conservation. Moreover, reducing the recession agriculture around the lake and wetland management could be crucial for improving lake water quality.

Groundwater Quality in an Upland Agricultural Watershed in the Sub-Humid Ethiopian Highlands

Agricultural intensification to meet the food needs of the rapidly growing population in developing countries is negatively affecting the water quality. In most of these countries such as Ethiopia, information on surface and especially groundwater quality is lacking. This limits the measure that can be taken to stop pollution. We, therefore, investigated the spatial and temporal variation of groundwater quality in the upland watershed. Tikur-Wuha watershed was selected because it is located in the Lake Tana watershed, which is seeing the first signs of eutrophication. Groundwater samples were collected from July 2014 to June 2015 from 19 shallow wells located throughout the watershed. Collected water samples were analyzed both in situ and in the laboratory to determine pH, electric conductivity (EC) and total dissolved solid (TDS), concentration of chemicals (nitrate, dissolved phosphorus, calcium, magnesium, aluminum and iron) and Escherichia coli (E. coli). We found that shallow groundwater had greater chemical concentrations and E. coli level in the monsoon rain phase than in the dry phase. Wells located down slope exhibited greater concentrations than mid- and upper-slope positions, with the exception of the nitrate concentration that was less down slope, due to denitrification in the shallow groundwater. Only E. coli level was above the WHO drinking water quality standards. Further studies on groundwater quality should be carried out to understand the extent of groundwater contamination.

Analysis of cotton water productivity in Fergana Valley of Central Asia

Cotton water productivity was studied in Fergana Valley of Central Asia during the years of 2009, 2010 and 2011. Data was collected from 18 demonstration fields (13 in Uzbekistan, 5 in Tajikistan). The demonstration field farmers implemented several improved agronomic and irrigation water management practices. The average values of crop yield, estimated crop consumptive use (ETa) and total water applied (TWA) for the demonstration sites were, respectively, 3700 kg/ha, 6360 m3/ha, and 8120 m3/ha. The range of values for TWA and ETa were, respectively, 5000 m3/ha to 12,000 m3/ha and 4500 m3/ha to 8000 m3/ha. A quadratic relationship was found between TWA and ETa. The average yield of the adjacent fields was 3300 kg/ha, whereas the average yield of cotton in Fergana Valley as a whole was 2900 kg/ha, indicating 28% and 14% increase in crop yield, respectively, from, demonstration fields and adjacent fields. There was no significant difference in crop yields between the wet years (2009 and 2010) and the dry year (2011), which is explained by the quadratic relationship between TWA and ETa. The water productivity values ranged from 0.35 kg/m3 to 0.89 kg/m3, indicating a significant potential for improving water productivity through agronomic and irrigation management interventions. The ratio of average ETa divided by average TWA gave an average application efficiency of 78% (some fields under-irrigated and some fields over-irrigated), the remaining 22% of water applied leaving the field. Since more than 60% of the water used for irrigation in Tajikistan and Uzbekistan is pumped from, even if all this 22% of water returns to the stream, substantial energy savings would accrue from improving the average application efficiency at field level. The range of values for TWA indicates the inequity in water distribution/accessibility. Addressing this inequity would also increase water productivity at field and project level.

Evaluation of Surface Water Availability for Inland Valleys Rice Production： The Case of Mankran Watershed in a Deciduous Forest Zone of Ghana

In Ghana, inland valleys have been found to be suitable for rice cultivation and could potentially increase lowland paddy rice production, This study estimated the temporal variations of surface water resources and their spatial distribution in the Mankran watershed of Ghana through the collection of recorded hydrological data in the bench mark watershedfrom2008 to 2010. Since most inland valley rice cultivation highly depends on rainfall, the watershed precipitation data over a decadal period showed sufficient wet years with a potential to sustain a high cultivation of paddy rice. Peak wetness occurred in June and October over a bi-modal precipitation pattern. Rating curve data for the Mankran-kesse river-upstream depicted low discharge values despite having a higher stream order. Thus stream order alone was not sufficient to estimate water resources potential. It was presumed that the geomorphology and lithology of the highly porous river bed and the presence of high sub-surface water resources stored in this zone may be implicated for this observation. Provision of water storage options for zones like Kesse-upstream seems a feasible option in order to cater for supplementary irrigation while indirectly tapping on subsurface water resources stored in the porous aquifers through basin interflows. Base flow data also showed that the discharge from upstream locations to the downstream exit of the watershed was high through direct surface river discharge and subsurface interflow. The temporal patterns of the hydrology indicate that annual paddy rice cultivation is ideal between May and October.

气候变化、土地利用/覆被变化及CO_2浓度升高对滦河流域径流的影响

在构建分布式水文模型与生物地球化学模型的耦合模型(DTVGM-CASACNP)及应用元胞自动机-马尔科夫(CA-Markov)土地利用预测模型基础上,以滦河流域为例分析气候变化、土地利用/覆被变化(LUCC)及CO2浓度升高对径流的影响。研究结果表明:DTVGM-CASACNP耦合模型以及CA-Markov模型在滦河流域均具有较好的适用性;气候变化与土地利用/植被覆盖变化对滦河流域径流的影响较CO2浓度升高的影响程度大;未来不同情景下滦河流域2020—2049年径流呈减小趋势,大部分情景下年径流较基准年减少,与非汛期相比,滦河流域未来汛期径流对不同情景更敏感,总体上在汛期径流相对基准年减少,而在非汛期径流相对基准年增加。

基于异源多时相遥感数据提取灌区作物种植结构

用遥感技术提取灌区作物种植结构需要源影像具有适宜的时空分辨率以适应其动态变化特征。该文综合运用多种遥感影像数据,将Landsat ETM+与MODIS NDVI数据融合区分灌区土地利用类型,由融合后的时间系列数据非监督分类结果提取植被指数变化信息,结合作物系数变化规律运用光谱耦合技术提取作物种植结构。根据该方法将漳河灌区作物种植结构区分为水稻—油菜、水稻—小麦、单季夏季作物以及双季经济作物。由地面统计数据和高分辨率IKONOS影像进行了检验,分类精度达到91%并且与统计数据相吻合。结果表明该法不仅能提供更为准确的灌区作物种植结构时空信息,而且节省影像购买成本,方便灌区尺度遥感应用。

A distributed modeling approach to water balance implications from changing land cover dynamics in permafrost environments

There is 78%permafrost and seasonal frozen soil in the Yangtze River’s Source Region(SRYR),which is situated in the middle of the Qinghai-Xizang Plateau.Three distinct scenarios were developed in the Soil and Water Assessment Tool(SWAT)to model the effects of land cover change(LCC)on various water balance components.Discharge and percolation of groundwater have decreased by mid-December.This demonstrates the seasonal contributions of subsurface water,which diminish when soil freezes.During winter,when surface water inputs are low,groundwater storage becomes even more critical to ensure water supply due to this periodic trend.An impermeable layer underneath the active layer thickness decreases GWQ and PERC in LCC+permafrost scenario.The water transport and storage phase reached a critical point in August when precipitation,permafrost thawing,and snowmelt caused LATQ to surge.To prevent waterlogging and save water for dry periods,it is necessary to control this peak flow phase.Hydrological processes,permafrost dynamics,and land cover changes in the SRYR are difficult,according to the data.These interactions enhance water circulation throughout the year,recharge of groundwater supplies,surface runoff,and lateral flow.For the region’s water resource management to be effective in sustaining ecohydrology,ensuring appropriate water storage,and alleviating freshwater scarcity,these dynamics must be considered.

一种简化蒸散发遥感反演模型及其在灌区的应用

提出简化的地表能量平衡模型(SSEB)将站点作物蒸散发量递推到整个灌区。首先由气象观测资料计算作物潜在蒸散发量,结合Landsat ETM+60 m热红外波段反演的地表温度差异把站点单日ET扩展到灌区,再融合ETM+和MODIS 1 km热红外时间系列数据,进一步提取全年灌区尺度蒸散发分布图。用湖北漳河灌区2000年的影像资料,将SSEB与SEBAL模型计算结果进行对比,结果表明,二者的决定系数R2达到了0.89。漳河灌区蒸散发主要来源于二、三干渠,年总蒸散发量中,作物蒸发蒸腾占67%,林地蒸散发占17%,水面加上裸地等其它用地的无效蒸散发占16%。

Development of Magnesium-Dominant Soils Under Irrigated Agriculture in Southern Kazakhstan

Irrational irrigation practices in the Arys Turkestan Canal command area in the southern part of Kazakhstan have led to the formation of soils with poor physical and chemical properties. To study whether irrigation and leaching practices and/or groundwater rise have contributed to the accumulation of Mg2+ on the cation exchange complex of these soils, historical changes in soil and groundwater quality were used as source data and the Visual MINTEQ model was applied to analyze the chemical composition of water and soils in the study area. The imposed irrigation regime and the leaching of light sierosem soils led to the dissolution and subsequent leaching of inherent gypsum and organic matter from the soil profile. Further, the domination of bicarbonate in the irrigation water promoted weathering of the carbonate minerals present as calcite. The higher concentrations of Mg2+ in comparison to Ca2+ in the irrigation water resulted in the replacement of Na+ by Mg2+ on the cation exchange complex. In the lower part of the command area, shallow groundwater has contributed to the accumulation of Na+ and to a large extent of Mg2+ on the cation exchange sites.

Disposal and Use of Sewage on Agricultural Lands in Pakistan: A Review

Raw sewage is widely used on agricultural soils in urban areas of developing countries to meet water shortages. Although it is a good source of plant nutrients, such sewage also increases the heavy metal load to soils, which may impact the food chain. Management options for sewage contaminated soils includes addition of nontoxic compounds such as lime, calcium sulfate and organic matter, which form insoluble metal complexes, thus reducing metal phytoavailability to plants. In this paper we review the variation in irrigation quality of sewage at different sites and its impact on the quality of soils and vegetables. Although quality of sewage was highly variable at source, yet the effluent from food industries was relatively safe for irrigation. In comparison effluent samples collected from textile, dyeing, calendaring, steel industry, hospitals and clinical laboratories, foundries and tanneries were hazardous with respect to soluble salts, sodium adsorption ratio and heavy metals like zinc, copper, iron, manganese, nickel, cobalt and cadmium. The sewage quality in main drains was better than that at the industry outlet, but was still not safe for irrigation. In general, higher accumulation of metals in fruits and vegetable roots was recorded compared to that in plant leaves, Edible parts of vegetables （fruits and/or leaves） accumulated metals more than the permissible limits despite the soils contained ammonium bicarbonate diethylenetriaminepentaacetie acid extractable metals within a safe range. In either case further scientific investigations are needed to ensure safe management strategies. Cadmium appeared to be the most threatening metal especially in leafy vegetables. It is advisable to avoid leafy vegetables cultivation in sewage irrigated areas everywhere to restrict its entry into food chain.

Use of Human Excreta as Manure in Rural China

Empirical research has shown that the use of manure significantly improves crop yield, soil fertility and water and moisture conservation. Despite these documented benefits, however, there is a concern on the downward trend of manure use in agriculture in China. This paper examines factors contributing to this downward trend, with a particular focus on human excreta used in agriculture. Empirical analysis based on data from stratified random sampling of rural households in five provinces of China shows that about 85% of human excreta was still used as manure in agriculture in 2007 which was less than a decade ago when nearly all human excreta was used as manure. Econometric results suggest that income growth, rising population density and improvement in rural transportation significantly contribute to declining use of human excreta as manure in agriculture. These results imply that the current downward trend will continue given China＇s rising economic growth, urbanization and rural infrastructural improvement.

Climate change adaptation, greenhouse gas mitigation and economic profitability of conservation agriculture: Some examples from cereal systems of Indo-Gangetic Plains

Achieving sustainability of the cereal system in the Indo-Gangetic Plains（IGP）of India under progressive climate change and variability necessitates adoption of practices and technologies that increase food production,adaptation and mitigation in a sustainable way.This paper examines conservation agriculture（CA）from the perspective of：（i）increased yield and farm income,（ii）adaptation to heat and water stresses,and（iii）reduction in greenhouse gas（GHGs）emissions.The analyses and conclusions are based on the literature and evidences from a large number of on-station as well as farmers’field trials on CA in the cereal systems of IGP.Our analyses show that CA-based system substantially reduces the production cost（up to 23%）but produces equal or even higher than conventional system;thereby increasing economic profitability of production system.CA-based production systems also moderated the effect of high temperature（reduced canopy temperature by 1–4°C）and increased irrigation water productivity by 66–100%compared to traditional production systems thus well adapting to water and heat stress situations of IGP.Our continuous monitoring of soil flux of CO2,N2O and CH4 revealed that CA-based rice-wheat systems emit 10–15%less GHGs than conventional systems.This is the first time that CA and its components are synthesized and analyzed from food security-climate change nexus.From this holistic analysis,we suggest that wide-scale promotion of suitable CA practices by integrating into national agriculture development strategy is a way forward to address food security,climate change adaptation and mitigation challenges faced by present agriculture.

Integrated soil, water and agronomic management effects on crop productivity and selected soil properties in Western Ethiopia

Land degradation is a major challenge limiting crop production in Ethiopia. Integrated soil and water conservation is widely applied as a means to reverse the trend and increase productivity. This study investigated the effects of such integrated approaches at two sites, Jeldu and Diga, inWestern Ethiopia. A split plot design with physical soil and water conservation in the main plots and agronomic practices in the sub plots was employed. Maize (Zea mays L.) followed by groundnut (Arachis hypogaea L.) at Diga, and wheat (Triticum aestivum) followed by faba bean (Vicia faba L.) were the test crops. Surface soils were sampled before sowing and after the crop harvest, and analyzed for selected parameters. Soil moisture content during the growing period was also monitored. The use of soil bund increased soil moisture content, and significantly (P < 0.05) increased days to flowering and maturity, kernel weight and harvest index, grain yield of the test crops, with the exception of maize. The improved agronomic practices (intercropping, fertilization and row planting) significantly (P < 0.05) increased grain yield of all the test crops. The effect of the treatments on soil parameters may require longer time to be evident. Although the increase in crop yield due to soil bund and the improved agronomic practices is eminent, economic analysis is necessary before recommending the widespread use of the improved options.

Impact of exclosures on wood biomass production and fuelwood supply in northern Ethiopia

In the Ethiopian highlands, communal grazing lands are one of the major land uses, and are source of livelihood for the rural people. Free and uncontrolled grazing in the communal grazing lands is the dominant grazing system. The traditional uncontrolled and free grazing system has caused severe degradation of the grazing lands. As a result, communities have started to establish exclosures and support the restoration of degraded communal grazing lands. Studies have shown that exclosures are effective to restoring degraded communal grazing lands and improving ecosystem services. However, studies that investigate the changes in aboveground biomass following the establishment of exclosures and compare it with fuelwood demand of the beneficiaries in our study area is lacking. Therefore, our study aimed at:(1) quantifying yearly biomass accumulation in exclosures and compare it to fuelwood demand of households that manage the exclosures;(2) assessing household energy sources and their consumption levels. To monitor changes in biomass production with over time, replicated(n = 3) 5 and10 year-old exclosures were sampled. To investigate fuelwood sources and consumption patterns, household surveys, key informant interviews and focus group discussion were conducted. Our results demonstrated that total biomass production increased with exclosure age. In both exclosure, biomass production from Vachellia etbaica was significantly(p \ 0.05) greater than that from Euclea.racemosa. Average daily fuelwood consumption per person was(0.63 ± 0.2) kg day^(-1). This means that the total biomass(27.5 Mg year^(-1)) obtained from 114.6 ha of exclosures covers only 9.4% of yearly fuelwood demand of the residents who manage the sampled exclosures. Nearly all respondents(95%) confirmed that they travel more than10 km day^(-1) to gather fuelwood from surrounding degraded forest patches. We recommend plantings of fast growing native tree species within exclosures and around homesteads to provide a sustainable fuelwood supply and using improved stoves to address the problem of fuelwood shortage. District agricultural offices could provide seedlings of native plant species, while communities provide unpaid labour for planting and managing plantations.