Assessment of a Non-Optical Water Quality Property Using Space-Based Imagery in Egyptian Coastal Lake

Progressively anthropogenic intrusion and increasing water demand necessitate frequent water quality monitoring for sustainability management. Unlike laborious, time consuming field-based measurements, remote sensing-based water quality retrieval proved promising to overcome difficulties with temporal and spatial coverage. However, remotely estimated water quality parameters are mostly related to visibility characteristic and optically active property of water. This study presents results of an investigated approach to derive oxygen-related water quality parameter, namely Dissolved Oxygen (DO), in a shallow inland water body from satellite imagery. The approach deduces DO levels based on interrelated optical properties that dictate oxygen consumption and release in waters. Comparative analysis of multiple regression algorithms was carried out, using various combinations of parameters;namely, Turbidity, Total Suspended Solids (TSS), Chlorophyll-a, and Temperature. To cover the wide range of conditions that is experienced by Edku coastal lake, ground truth measurements covering the four seasons were used with corresponding satellite imageries. While results show successful statistically significant correlation in certain combinations considered, yet optimal results were concluded with Turbidity and natural logarithm of temperature. The algorithm model was developed with summer and fall data (R2 0.79), then validated with winter and spring data (R2 0.67). Retrieved DO concentrations highlighted the variability in pollution degree and zonation nature within that coastal lake, as related to boundary interactions and irregularity in flow dynamics within. The approach presented in this study encourages expanded applications with space-based earth observation products for exploring non-detectable water quality parameters that are interlinked with optically active properties in water.

Application of Geographic Information Systems in Groundwater Prospecting: A Case Study of Garissa County, Kenya

Groundwater prospecting in Kenya has been haphazard and expensive due to lack of information on the appropriate areas for hydrogeological exploration and drilling of boreholes. Drilling in areas without prior knowledge about their groundwater potential has been leading to the drilling of numerous dry boreholes. In this study, we explored the use of Geographic Information System as a pre-analysis tool to identify zones with groundwater potential for Garissa Country. Factors that contributed to groundwater occurrence were identified as landcover, soil type and rock formation. The groundwater potential zones were generated by analysing thematic data of the three factors and integrating the musing Weighted Index Overlay Analysis (WIOA) method. The groundwater potential zones were validated by comparing the predicted potentials with actual yields of existing boreholes drilled within those areas. Results indicate that, whereas the model correctly predicted areas with low or no groundwater potential, it performed sparingly well when predicting areas with good groundwater potential. The study conclusively identified areas where groundwater prospecting should not be attempted and other alternative methods of surface water provision should be explored.

Discussion on Irrigation Development and Its Investment Focus in Tanzania

This paper describes the significance of irrigation on economy development and the status of irrigation development in Tanzania, analyzing the potential and advantages of irrigation development in this country, combined with the major initiatives and experiences which can learn from in the recent 30 years of rural water conservancy in China. Then it discusses the next investment focus on irrigation development for Tanzanian.

Strategy to Overcome Barriers of Rainwater Harvesting, Case Study Tanzania

There are socio-technological challenges towards extension of the application of rainwater harvesting (RWH) practices in developing countries. An attempt to address this was done using the Mnyundo Primary School, Tanzania, as a study area for evaluating the technical, economic, and social challenges of RWH practices. A storage water level monitoring gauge was used so as to simplify rainwater quantity control and utilization strategy. Basic quality control components such as first flush tank were incorporated so as to reduce the particle load flowing into the storage. Cost reduction strategies such as the one (1) company one (1) community campaign were applied to address the cost implication. To enhance ownership, participatory approach of the beneficiaries in all stages including planning, designing and implementation was adopted. In order to ensure project sustainability, training on how to operate and maintain were provided as well as a maintenance manual to impart a sense of ownership. For the challenges of imparting RWH practices in Tanzania, 19 solutions have been identified and they include provision of RWH manuals, guidelines and regulations, government incentives, and promotion of self-financing initiatives. For developing countries, the study proposes the following strategies: establishing relevant regulations and research centers, enhancing individual and community financial stability, conducting demonstration projects, and increased investment by government on promotion.

Geophysical Investigation Using Time Domain Electromagnetic Method (TDEM) at Wadi Deir Al-Kahaf Area/Jordan for Groundwater Artificial Recharge Purposes

In this study, Ten Time Domain Electromagnetic (TDEM) measuring points have been conducted at four pre-selected sites along Wadi Deir Al-Kahaf in order to investigate the potential of the near subsurface deposits and aquifer for groundwater artificial recharge applications. The surveyed results suggest well resolved geological layers such as alluvial mudflat, basalt layers and their saturation states. In addition a hydrogeophysical cross section along the studied sites was constructed which permits to locate the lateral variations in rock properties due to water saturation and or facies changes. The saturated thickness of the Upper Aquifer System in the study area was found to be changed from 5 m near TEM 1 to about 120 m near TEM 4 in thickness. The Abed Basalt Aquifer (AOB) has an average saturation thickness of about ~60 m, and forming the main aquifer (~100 m thickness) near surface to the north of the study area. TEM-3 and TEM-4 sites were found to be potential sites for groundwater artificial recharge based on the constructed hydro-geophysical model. This study recommends implementing detailed geophysical investigations particularly in the most northern parts of the study area.

Groundwater Vulnerability for the Surface Outcropping Aquifers in Jordan

Groundwater vulnerability is an overlay method that is used to determine the ability of pollutants to penetrate to the target aquifer and to harm it. This method helps decision makers by shedding light on pollution areas expected to pollute groundwater aquifers as caused by human activities on the ground surface. In Jordan, groundwater is the main water resource the country uses to match its demand. The groundwater basins in Jordan are divided into 12 major basins. Some basins are rechargeable and other basins are fossil. Many basins are over exploited. Amman Zarqa basin is a clear example for this case. Others are saline just like Azraq basin and the rest is expected to be affected by the growing demand for agricultural, municipal and industrial activities. In this study, a groundwater vulnerability map was produced for Jordan using DRASTIC index to study the vulnerability of the shallow aquifers throughout the country. The map shows different vulnerability classes ranging from low to very high reflecting the environmental, hydrological and hydrogeological settings of the groundwater and its recharge ability. The resulted map shows wide variation in groundwater vulnerability in different sites in Jordan. Areas with higher vulnerability are those with friable aquifer materials and shallow groundwater depths. Medium and low vulnerability classes are exist too because of the variations of the environmental settings within the targeted areas.

Strategies for Household Water Supply Improvement with Rainwater Harvesting

There are significant household water supply challenges including quantity sufficiency and quality, which have economic and social implications. The challenges have remained despite the efforts of government establishing centralized or groundwater systems, and/or having individual crude systems. A Tanzanian rural household case study was considered by assessing the performance of a currently relied surface runoff collecting pond system for domestic purposes. A daily water balance model was applied with performance parameters, no water days (NWD) and rainwater usage (RUR). Rooftop runoff harvesting system was proposed as a water supply source in addition to the current one. Under such dual supply conditions, users can meet the drinking and non-drinking demand even in dry seasons at a minimum of 2 and 20 L/person/d, respectively. For rainwater harvesting adoption (considering selected regions), it was further established that amount and variation in rainfall impacts on quantity available for meeting demand. Increased catchment implies increased harvestable quantity, and with same storage higher reduction of number of NWD although with slight decrease of RUR. Also, increased storage is required for achieving higher RUR in case the same demand is maintained. But same storage can be maintained for increased demand relative to catchment size. However, rainwater catchment increase has greater impact on meeting a specified demand under given condition of rainfall quantity and variation. The RWH technology strategies presented in this study are replicable in other developing countries under site specific conditions.