Integrated Water Resources Management Research Articles

Tackling water scarcity in agriculture—Asian Development Bank's perspective

Abstract‘Tackling water scarcity in agriculture’, which is the theme of the 25th Congress of the International Commission on Irrigation and Drainage (ICID), is at the crux of the global challenge of ensuring a climate‐resilient and water‐ and food‐secure world for future generations. The Asian region faces significant threats due to its high vulnerability to climate change impacts and growing food insecurity and water stress across many river basins. The Asian Development Bank (ADB) is stepping up assistance in line with the international commitments by the multilateral financial institutions. There are significant opportunities that are tapped to address this theme, including (i) exploring and replicating highly successful experiences of enhancing irrigated agriculture productivity manifold as seen in the Indian states of Chhattisgarh, Karnataka and Madhya Pradesh and in other South Asian countries; (ii) reinvigorating efforts to operationalize integrated water resources management in river basins; (iii) adopting new technologies, such as remote sensing and automation, and digital technologies, including artificial intelligence; and (iv) pursuing institutional and financing innovations. Resources of ADB and other multilateral institutions can be utilized to develop and demonstrate successful innovations before they are replicated by the own sources of the developing countries.

Two Decades of Integrated Flood Management: Status, Barriers, and Strategies

Losses from flood disasters are increasing globally due to climate-driven forces and human factors such as migration and land use changes. The risks of such floods involve multiple factors and stakeholders, and frameworks for integrated approaches have attracted a global community of experts. The paper reviews the knowledge base for integrated flood risk management frameworks, including more than twenty bibliometric reviews of their elements. The knowledge base illustrates how integrated strategies for the reduction of flood risk are required at different scales and involve responses ranging from climate and weather studies to the construction of infrastructure, as well as collective action for community resilience. The Integrated Flood Management framework of the Associated Programme on Flood Management of the World Meteorological Organization was developed more than twenty years ago and is explained in some detail, including how it fits within the Integrated Water Resources Management concept that is managed by the Global Water Partnership. The paper reviews the alignment of the two approaches and how they can be used in tandem to reduce flood losses. Success of both integrated management approaches depends on governance and institutional capacity as well as technological advances. The knowledge base for flood risk management indicates how technologies are advancing, while more attention must be paid to social and environmental concerns, as well as government measures to increase participation, awareness, and preparedness. Ultimately, integrated flood management will involve solutions tailored for individual situations, and implementation may be slow, such that perseverance and political commitment will be needed.

Enhanced groundwater availability through rainwater harvesting and managed aquifer recharge in arid regions

Climate change in desert areas and semi-arid watersheds may offer a promising solution for the water scarcity problem that Bedouins and local inhabitants face. This study investigated the integrated water resources management in arid and semi-arid regions using rainwater harvesting in combination with the managed aquifer recharge (RWH-MAR) technique. The study also used recharge wells and storage dams to achieve the sustainability of groundwater supplies in the context of climate change and management of the flow to the Gulf of Suez. Therefore, different return periods of 10, 25, 50, and 100 years were considered for the annual flood volume resulting from those watersheds. Moreover, hydrologic modeling was carried out for the El Qaa plain area, South Sinai, Egypt, using the Watershed Modeling System (WMS) and the groundwater modeling of SEAWAT code. Our findings show that for different scenarios of climate change based on return periods of 10, 25, 50, and 100 years, the aquifer potentiality reached 24.3 MCM (million cubic meters) per year, 28.8 MCM, 36.7 MCM, and 49.4 MCM compared to 21.7 MCM at 2014 with storage of groundwater ranges 11.8%, 32.1%, 69%, and 127.4%, respectively. These findings have significant implications for the system of RWH-MAR and groundwater sustainability in El Qaa Plain, South Sinai. The RWH-MAR proved to be an effective approach that can be applied in different water-stressed and arid regions to support freshwater resources for sustainable future development and food security, as well as protect communities from extreme flash flood events.

Technical and economic impact of water reuse as an integrated water resource management measure in rural water supply systems

ABSTRACT Water reuse becomes an alternative in the conventional water supply systems, especially in regions where nonpotable use of drinking water, as for garden and grass irrigation, is predominant. This study evaluates the footprint of reuse on small water supply systems in rural areas, where raw water quality does not meet the drinking water standards, and complicated treatment is needed. Individual facilities for the reuse of potential rainwater, light gray, gray, and domestic wastewater in the households could lead to a decrease in nonpotable tap water use up to 60% and a decrease in households' annual expenses for water supply up to 93 €/household. The installation of individual facilities for common reuse of rainwater and gray wastewater requires the highest investment costs, but the optioǹs operational costs are between 15 and 20% lower than all other options considered. The drinking water treatment plant capacity reduction due to measures’ implementation enables from 48 up to 58% saving in the total operational costs for drinking water supply in the settlement. The shortest payback period and best economic impact of reuse for small-scale water supply systems are observed if rainwater and gray wastewater are reused together.

Resilience framework for urban water supply systems planning

ABSTRACT As the concept of resilience is becoming a criterion in planning, water utilities are seeking support and practical guidance to enhance their conventional risk-based planning processes. This paper presents a resilience framework for urban water supply systems planning during the transition towards integrated water resources management. Based on a synthesis of literature across engineering, ecological and social sciences, resilient system performance is defined using crossings of fail-safe and safe-fail thresholds as key indicators. System performance curves conceptually illustrate the capabilities withstanding, absorptive, restorative, adaptive, transformative, and anticipative (WARATA), during sudden and gradual disruptions. Sustainability goals are explicitly considered in the resilience framework, and the role of transformative and anticipative capabilities to facilitate transitions is discussed. Specifically, the desirability of physical design and predicted community consequences from performance impact and collapse can be used in resilience management to prioritize between fail-safe and safe-fail system capacities. Finally, key considerations for operationalizing the framework are summarized, including how issues related to social justice can be addressed when simulating performance and deriving metrics. While this paper focuses on urban water supply, the framework could be applied to other service-providing infrastructure where resilience-based planning supported by quantitative evidence is required to inform investments.

International donors as agents of policy transfer in influencing water legislation: The adoption of the river basin principle by transition economies in Eastern Europe, Caucasus and Central Asia

Over the past decades, political scientists have studied how the policies and ideas of one political setting are used in the development of policies in another political setting, a process known as ‘policy transfer’. In the case of such transfer from one country to another, the role of various institutions and networks as ‘agents’ of policy transfer becomes central. Many researchers have mapped the role of the international donor community as an agent of transfer of Integrated Water Resources Management (IWRM) principles in developing economies. This article examines the case of 11 transition economies from Eastern Europe, Caucasus and Central Asia (EECCA) to establish whether the role of the international donor community has been similar in exporting the IWRM concept, along with its key river basin principle, into national legislation. Roughly a decade after these 11 former Soviet republics gained independence in 1991, a ‘window of opportunity’ emerged when the need arose to revise the national water legislation that had been developed according to old Soviet approaches. The present analysis finds that international donors such as the EU, the US and UN agencies have played a significant role as transfer agents, being involved in shaping at least 18 out of 23 key national water laws, programmes or concepts in the selected countries between 2002 and 2023. The article concludes that 10 countries have adopted IWRM basin management principle and one is expected to follow soon as a result of a process involving international donor engagement.

Transboundary water resource management and sustainable development in the lancang-mekong river basin: an analysis of international water law

ABSTRACT The Lancang-Mekong River Basin stands as one of the most critical and complex transboundary basins globally, where the utilization and protection of water resources are paramount. This basin, linking China, Myanmar, Laos, Cambodia, Thailand, and Vietnam, is characterized by a dense population and rapid industrial and agricultural development, fostering frequent economic and cultural exchanges. Cooperative efforts in water resource utilization and protection among these countries lead to issues such as resource disputes, environmental pollution, and collaboration barriers. Since the six basin countries have not jointly joined any international convention on water resources development or protection, disputes have been resolved and cooperation promoted through existing inter-state cooperation mechanisms for many years. However, these mechanisms often fall short due to the lack of common guiding principles. Achieving sustainable water resource development in the Lancang-Mekong River Basin aligns with the national interests of the six countries. The basin states can establish a transboundary Environmental Impact Assessment system and a dispute settlement mechanism. Constructing a comprehensive Integrated Water Resource Management Cooperation Mechanism, rooted in the fundamental principles of international water law, is crucial for enhancing the level of international cooperation within the basin.

Water Resources Management under Climate Change: A Review

Climate change affects water resources through the decrease in rainfall and the increase in temperatures and evapotranspiration. An indirect impact of climate change is also the increase in water uses by human activities. In this review, 320 papers were retrieved, of which 134, spanning five continents and dealing with impacts and solutions, were selected to be used to better understand the effects of climate change on water resources, ecosystems, human health, security, and socio-economic aspects. Here, suggestions and proposals towards solutions by scientists from around the world, tips and ideas to deal with climate change, and the best solutions for future water management are presented. The main solutions highlighted concern integrated water resource management, political direction, policies, an increase in knowledge, and new technologies. Furthermore, most of the analyzed papers underline that water resource management needs to incorporate the protection and restoration of ecosystems and their services. Nature-based solutions need to be the starting point of new scientific and innovative ways to deal with climate change and look towards future climate adaptation. In this complex evolution of the water resource, the political position of Italy is also shown, illustrating what actions could be implemented for water resource management.

Hydrogeochemical analysis of groundwater quality during the pre- monsoon season of Manipur, India

ABSTRACT The water quality index (WQI) and irrigational index for groundwater were studied in the northeastern section of the Manipur Valley in northeast India. Water samples were collected in 2022 during the pre-monsoon season. To compute the water quality index for drinking water, the basic chemical parameters of total hardness, pH, electrical conductivity, total dissolved solids, Calcium, Sodium, Iron, Magnesium, Manganese, Chlorine, and Hydrogen Carbonate were used. The assessment of bacteriological quality is also done, which is crucial for overall water quality evaluation, alongside physical and chemical analyze. For determining irrigation suitability, irrigational indices such as sodium absorption ratio, sodium percentage, and magnesium hazard were calculated. WQI, %Na+, Sodium Adsorption Ratio (SAR), magnesium hazard, permeability Index and total hardness indicate that most water samples are harmless for irrigation and drinking purpose. They have affirmative relationships indicating that these characteristics are interdependent. Approximately 25% of the Piedmont zone groundwater is found to be unfit for agricultural and drinking usage. The encrustation of gypsum, halite, and evaporation into the Disang shares accelerate the dissolution of ions in Piedmont water, resulting in quality degradation. According to Gibbs plots, Durov Scatter Plot, and Hill Piper Trilinear Diagram of water dominated the rock-weathering process, while hydrochemical facies progressed from the beginning to the intermediate stage of Chadha’s graphical representation illustrates the progression of hydrochemical processes in surface water. Therefore, proper integrated water resource management and development are required for effective water resource utilization, particularly around the Piedmont zone. In recent years, the quality of groundwater has caused a significant deal of alarm, and an increasing number of studies relating to it have been published. The geological, structural, and geomorphological features in the intermontane Imphal Valley in Manipur, India, were identified using SRTM DEM data by QGIS Software. This area has simple geology and structural elements, making it an appropriate site to evaluate the use of remote sensing and GIS tools in geological studies. To prevent a water crisis, groundwater resources must be managed sustainably. The current study also concentrated on a bibliometric examination of groundwater management and access to gauge the state of the field. A bibliometric examination of these papers may offer insight into current research and trends. We are the first to join Groundwater Quality Assessment with bibliometric analysis. This prediction, if taken into consideration strategically during the planning of preventive measures for groundwater quality can help to analyze future evaluation to a great extent.

Effects of climate variability and/or land use dynamics on the hydrological balance of the Cavally river catchment at Toulepleu, West Africa

Abstract The study focuses on assessing the individual and combined impacts of climate variability and land use change on hydrological responses. The results indicate that the basin, urban area, cropland, degraded forest, and open forest shows an increasing trend, while gallery forest show a decreasing trend over the period 1992–2015. Climatic variability is marked by two climatic periods (a wet one from 1980 to 1996 and a dry one from 1997 to 2016) with a 35% decrease in rainfall. Regardless of the state of the landcover used, the simulated mean annual runoff decreases by 67.92% between the wet and dry climate periods. Changes in land use between 1992 and 2015 reduce mean annual runoff by 4.71%. Analysis of the joint effect of climatic and LU variation shows a 68.96% reduction in runoff. In this catchment, the joint impact has a clearly greater effect on runoff than the climatic impact, which is greater than that of human activities. There is a need for policymakers to prioritise sustainable land use practices and integrated water resource management strategies in the area to mitigate the combined effects of climate variability and anthropogenic activities, ensuring the long-term resilience of the ecosystem and water availability for local communities.

Polycentric Groundwater Governance: Insights from the Kavango-Zambezi Transfrontier Conservation Area

This paper analyses groundwater governance within a transfrontier conservation landscape. Given the current heightened interest in groundwater development, it is imperative that more thought be given to how groundwater resources can best be managed in different contexts for multiple uses and users. Transfrontier conservation areas are areas of vast biological diversity whose functioning and ecosystem integrity depends on the availability of water to sustain ecosystems and subsequently derive economic benefit. Further, climate vulnerable rural communities depend on and form an important part of this landscape. The work highlighted in this paper is based on a study conducted in parts of the Kavango-Zambezi Transfrontier Conservation Area (TFCA), the largest TFCA in the world. Climate induced challenges such as droughts and general poor land use planning have resulted in threats to long term sustainability of freshwater ecosystems and increased incidences of human-wildlife conflicts over limited water resources. Effective groundwater governance can potentially provide pathways for alleviating these challenges. Building on the theoretical fundamentals of polycentric governance, this paper analyses the case of the KAZA TFCA in which multiple levels of governance exist. The paper discusses how to achieve coordination and accountability within a shared landscape to foster sustainable use and management of groundwater. Groundwater within a TFCA context has the potential to alleviate human-wildlife conflict over freshwater, support groundwater dependant ecosystems and sustain smallholder agriculture for the rural communities. Understanding this role of groundwater adds to the framing of freshwater governance and conservation efforts within a TFCA and the identification and development of platforms for the integrated management of groundwater. Bringing together freshwater and conservation institutions in a multi-country context towards integrated water resource management is an initial and novel attempt which forms the foundation for achieving optimal governance approaches in the commons.

Dam the river: Ontological exclusion in global and Brazilian Integrated Water Resources Management

Integrated Water Resource Management (IWRM) has been widely adopted as a norm that promises to increase equality and sustainability of water governance through participatory decision-making. After decades of policy implementation, however, inequalities in outcomes and large-scale water-related disasters raise questions about the ability of IWRM to deliver on its promises. This article explores these questions by putting the history of IWRM at the global scale in conversation with the national scale of water governance in Brazil and the local scale of the Rio Doce, the site of the largest single environmental disaster in Brazilian history. This conversation highlights truncated practices of inclusion in which participation of diverse actors is possible only within an account of water as a resource system. Mobilizing recent debates about the Ontological Turn in social sciences and humanities, we argue that the appeal to inclusion in IWRM masks ontological exclusion in which participation is dependent on an ontology of water as a resource system. The case of the Rio Doce shows how promises of equality and sustainability through inclusion fail in the light of rendering local ontologies invisible or illegitimate for governance. In framing IWRM as a site of ontological inequality, groundwork is laid for a renewed promise of participation.

The Dialectics of Nature–Human Conflicts for Sustainable Water Security

How humans use and manage water resources under climate change conditions threatens water security, which means risking the availability of enough good-quality water for everybody and for nature’s flora and fauna. Integrated Water Resources Management is a state-of-the-art water management model. After 20 years in use, the application of this model failed to achieve its primary goal in many countries, i.e., ensuring the good ecological status of rivers, lakes, and aquifers. This paper shows that because the model is more human-centered than nature-oriented or anthropocentric, it generates severe environmental damages called “externalities.” From a historical analysis of the human–nature interplay, three main results were obtained: (1) the nature–human interaction is always in a state of contradictory confrontation, being composed of two opposite human behaviors of conflict and cooperation with nature; (2) this contradiction is assumed as a general ontological principle and epistemic hypothesis, called “dialectical”; and (3) historically, in the balance of power between nature and humans, three clusters are identified: (i) naturalistic, (ii) dualistic, and (iii) anthropocentric. A theory of a novel behaviorist conflict resolution model is suggested to dialectically resolve conflicts between stakeholders and natural laws. This model provides a harmonic symbiosis of humans and nature, removes environmental externalities, and can lead to sustainable water security. Three case studies illustrate the merits of the new dialectical model in real applications.

Water footprint assessment in an industrial symbiosis system based on environmental, economic, and social sustainability indices

Integrated water resource management requires a comprehensive assessment of all water uses, both direct and indirect, which can be captured by the Water Footprint (WF) concept, especially in Industrial Symbiosis (IS). IS creates links between different industries to reduce resource consumption. This article analyses the environmental, social, and economic sustainability aspects of the WF in an IS system. First, the inventories of these three aspects were carried out simultaneously with the WF inventory. Sustainability indices were presented based on the relative comparison of current WF and sustainably oriented WF (SOWF). SOWF in an IS system is defined as the situation with minimum total WF and is obtained by mathematical programming. The proposed framework was applied to an IS involving three industries in southeastern Iran: steel production, coal concentrate, and power generation. The blue WFs of these industries were calculated as 11.77 m3/ton of steel, 0.87 m3/ton of coal, and 8.31 m3/MWh of power. The sustainability indices revealed that the steel industry exhibited a more favorable environmental and social performance than other industries, while the power generation was economically superior with a higher cost ratio of current WF to SOWF. Subsequently, several sustainability-enhancing solutions were evaluated based on environmental, economic, and social criteria. Among these, solar energy usage, wastewater reuse, and recycling in iron ore processing emerged as effective strategies to enhance overall sustainability by reducing WFs and improving social criteria. Ultimately, the wastewater reuse option was given the highest priority.

ASSESSING THE IMPACT OF LAND COVER AND LAND USE CHANGE ON URBAN INFRASTRUCTURE RESILIENCE IN ABUJA, NIGERIA: A CASE STUDY FROM 2017 TO 2022

The remarkable feature of rapid urbanisation, which has fundamentally altered the distribution of land cover and land use (LULC), is what sets the contemporary era apart. The impact of these modifications on the resilience of Abuja’s metropolitan infrastructure from 2017 to 2022 is examined in this study. Our study examined the dynamic changes in LULC using information from remote sensing, geospatial analysis software, and land cover categorization techniques. The findings indicate major changes in Abuja’s topography, including a decrease in the number of water bodies, a decrease in the number of trees, the expansion of urban areas, changes in agricultural land use, and fluctuations in the amount of grazing land. The previously mentioned changes have significant consequences for urban infrastructure resilience, affecting various sectors such as water supply, transportation, housing, utilities, and food distribution systems. The infrastructure supporting water supply and sanitation may be severely stretched as the number of water bodies decreases, affecting the quantity and quality of accessible water supplies. As metropolitan areas expand, greater strain is placed on transportation infrastructure, exacerbating traffic congestion and complicating road maintenance ifficulties. Changes in agricultural land use can have an impact on food production and distribution, hence affecting food security. Deforestation can cause ecological deterioration, affecting a variety of aspects such as temperature regulation, biological diversity, and atmospheric purity. Adaptive approaches, green infrastructure, and adopting sustainable urban design can all strengthen the resilience of urban infrastructure, according to this study. The significance of renewable energy adoption, community participation, green building laws, the establishment of public-private partnerships, integrated water resource management, and data-driven decision-making is emphasised. Improving legal frameworks that prioritise resilience and sustainability is critical. It is critical to have a complete grasp of the complicated links between changes in LULC, and the resilience of urban infrastructure in order to enable educated urban design and decision-making processes. Policymakers and urban planners may address and minimise the negative consequences of climate change while improving the overall quality of life in cities by using sustainable development practises. The findings of this study have the potential to dramatically improve Abuja’s people’s well-being and sustainability, especially given the variety of urban difficulties they encounter.

Analisis Potensi dan Kemajuan dalam Pengelolaan Air Bersih dan Sanitasi Berkelanjutan (SDGs 6) di Indonesia

The aim of this research is to provide an analysis of how efforts have been made to achieve Sustainable Development Goal number six (SDGs 6), namely Clean Water and Sanitation. The main focus of this research is to assess the implementation of policies and projects related to water and sanitation and understand the impact they will have on society and the environment. This study collects data from government reports and other relevant research. Universal access to clean drinking water, adequate sanitation, efficient water use, and protection of water ecosystems are the main indicators of SDGs 6. The research results show great progress in achieving SDGs 6 in several aspects. Access to clean water has increased and many sanitation projects have been implemented successfully. Challenges remain, especially in achieving sanitation goals in rural areas and in managing water quality. Integrated water resource management and protection of water ecosystems are highlighted in this analysis. The research also underscores the need for international cooperation and community participation in addressing clean water and sanitation challenges. Data limitations and unequal access continue to be important issues that need to be addressed. Therefore, this study recommends increased detailed data collection and capacity building of local communities. By detailing the challenges and potential solutions, this research contributes to a deeper understanding of achieving SDGs 6. The implications of these findings can help civil society in designing more effective policies and projects to achieve clean water and sustainable sanitation.

POLITICAL AND ECONOMIC ASPECTS OF INTEGRATED URBAN WATER RESOURCES MANAGEMENT (IUWRM) IN SEMARANG CITY INDONESIA

Purpose: This study aims to find out the aspects of politics and economics of integrated urban water resources management in Semarang City and their impact on the practices of qualities of water resources management.   Methods: This research used the qualitative method and field research approach. The focus data are the regulation and the implementation of water resources management in Semarang City Indonesia. The data was drawn from documents and interview with some resource persons.   Results and Conclusion:  The study found that the city government, which should carry out the function of conserving water resources, actually polluted the Kaligarang River through one of its institutions: Local Water Drinking Company, “Tirta Moedal”. This company disposes of waste sludge containing aluminum metal directly into the river without any treatment processes that impacted in pollution in the river and causing siltation of the river downstream.   Research implications: the enactment of the comprehensive and integrated water resources management will has a positive impact on the practices of water resources management in Semarang specifically and Indonesia and even world countries generally. The implementation of comprehensive and integrated water resources management will also support the achievement of the sustainable development Goal.   Originality/value: Semarang City government must be supported to arrange a comprehensive and integrated water resources management (WRM) policy. There must be a clear legal law for the water resources management.

Characterization of subsurface geology and hydrogeology in Kribi -Cameroon using electrical resistivity soundings and 3D-Implicit modelling: Baseline for groundwater resource management

This scientific article aims to characterize the geology and hydrogeology of Kribi, Cameroon for the purposes of water resources management, infrastructure development, and environmental protection. The specific objectives include mapping the subsurface electrical resistivity structure, identifying groundwater potential zones, and constructing a hydrogeological model for groundwater modelling. The study employed the Schlumberger method to map the electrical resistivity structure of the 3D subsurface and utilized 3D implicit modelling techniques to delineate groundwater potential zones. The study revealed that Kribi exhibits a highly complex geology, characterized by three-layered electrical resistivity models, typical of sedimentary and metamorphic formations. The major lithologies identified include laterite, clay, sand, quartz, and granite. The region encompasses areas with low water potential and brackish zones alongside high groundwater production areas. The study established the presence of aquifers within Kribi, with the unconfined aquifer found at depths ranging from 2 m to 13 m, and the confined aquifer extending from 14 m to 40 m. The aquifers are notably thick and productive, indicating substantial groundwater resources. Static groundwater volumes were estimated at 50,179,381 m3 and 317,118,946 m3 for the unconfined and confined aquifers respectively. Despite this potential, water resources management in the area is non-existent. The study recommends the implementation of Integrated Water Resources Management (IWRM) to improve water resource management, with a primary focus on groundwater modelling. The northern and southern regions of Kribi exhibit high permeability, which is advantageous for groundwater recharge and storage projects but also poses challenges for environmental remediation efforts. Consequently, safeguarding the delineated area for groundwater provision is of utmost importance.

Groundwater development and management constraints in drought prone Chiredzi and Zvishavane Districts, Zimbabwe

Communities in drought-prone areas continued to fall into new vulnerability traps due to increasing water demand and stress. The study assessed groundwater development and management constraints in the Chiredzi and Zvishavane districts of Zimbabwe. Groundwater development and management activities implemented in the study area were supported by the Government of Zimbabwe, development partners, humanitarian agencies, private sector corporate social responsibility, and individual households. Interpretivism and realism philosophical positionalities were employed in the study. Whilst interpretivism’s inductive approach enabled an in-depth qualitative methodology and understanding of the groundwater constraints, the direct realism provided quantitatively driven scientific and statistical data to answer the research questions exhaustively. Quantitative data was gathered through a household questionnaire administered to randomly selected respondents. Qualitative data was gathered using focus group discussions, key informant interviews, direct field observations and measurements. Respondents to the key informant interview were drawn from district-level government officials, local authorities, traditional leaders, village pump minders and water point committee members.Due to climate change, communities have experienced an increase in the decline in groundwater levels during the dry season evidenced by demand surpassing supply. Temperature increase and rainfall decline experienced by 97%, and 73% of respondents from Chiredzi and Zvishavane districts, respectively, resulted in increased withdrawal and reduced groundwater recharge. Participants revealed that groundwater withdrawal is on the increase while recharge is declining as evidenced by the increase in conflicts at waterpoints. The 85% coverage by low groundwater-yielding basement hydrogeological formation suggested a slight reduction in groundwater recharge due to reduced rainfall and increased community vulnerability to drought. Village Pump Minders and Water Point Committees experienced operational challenges that affected the maintenance of groundwater sources. This was mainly due to the incapacitation of local institutions in terms of financial resources, equipment, and skills. The study recommends a groundwater replenishment model to improve groundwater aquifer recharge. Strengthening of local institutions improves the management of groundwater using integrated water resources management (IWRM) framework that promotes coordination between competing uses.

FORECASTING OF FLOOD EVENTS FOR WATER RESOURCES MANAGEMENT IN GUCHA-MIGORI RIVER BASIN, KENYA

Floods are devastating natural disasters frequently occurring in many river basins such as Gucha-Migori River Basin, Kenya. However, non-structural countermeasures such as hydrologic modelling, flood proofing, and continuous forecasting have not been fully explored and implemented to reduce risk, damage, and vulnerabilities of flood events. The major challenge in flood forecasting is the selection of the relevant probability distribution. The main objective of the study was to forecast flood events in Gucha-Migori River Basin for integrated water resource management. Daily hydrological datasets between 1969 and 2015 were obtained from Water Resources Authority. After the ranking of independent flood events had been achieved, return periods and flood frequencies were computed. The relationship between flood magnitudes and their respective frequencies was through modelling using probability distribution functions (PDFs). The evaluated PDFs include Normal Distribution, Log-Normal Distribution, Gumbel Distribution, and Log-Person Type III Distribution. Coefficient of Determination (R2), Goodness of Fit test, and Best-Fit Distribution Curve guided selection of the suitable distribution model. The suitable probability distribution model out of the tested four was then applied to predict P-percent annual exceedance probabilities corresponding to specific flood magnitudes. From the results, out of the 132 flood events that occurred in the period 1969 to 2015, only 42 were identified as independent flood events. Based on the frequency analysis, the highest and lowest, and the average and standard deviation of the recorded independent flood events were 423.90, 240.8, 284.80 m3/s, and 45.54 respectively. It was revealed that the probability of a flood event of a magnitude equal to or exceeding the lowest (240.8 m3/s) and the highest (423.90 m3/s) occurring for a particular year were 0.98 and 0.02 respectively. Gumbel distribution curve was selected to be the best fit for the Gucha-Migori River Basin. According to the derived Gumbel's formula, the estimated magnitude for the return period 1.05, 1.11, 1.25, 2, 5, 10, 25, 50, 100, and 200 years were 221.38, 231.92, 245.77, 278.01, 321.39, 350.11, 386.39, 413.31, 440.03, and 466.65 m3/s. This research provides useful information for enhanced determination of probability occurrence of flood events and thus proper water resources planning and management strategies in the Gucha-Migori river basin.