A socio-environmental model for exploring sustainable water management futures: Participatory and collaborative modelling in the Lower Campaspe catchment

Operational performance improvements in irrigation canals to overcome groundwater overexploitation

Optimal Conjunctive use of Surface and Groundwater under Fuzzy Environment

In China, irrigation plays a significant role in guaranteeing national food security. However, with the development of society and the economy, water resources have become increasingly short and the conflict between water supply and requirement is worsening in irrigation districts. How to optimize and allocate the limited water resources has become a research focus. Combining groundwater and surface water for agricultural irrigation is an effective approach to solve the problems. It is helpful to regulate and utilize the limited water resources more reasonably by conjunctive use of surface water and groundwater. It is also significant in protecting the environment and promoting sustainable development of irrigation districts. In this paper, the definition, principles and advantages of conjunctive use of surface and groundwater are introduced. Then related research is discussed from the perspectives of the research objectives, computing model and methodology. Study of the model on conjunctive use of surface and groundwater in irrigation districts is of great practical significance for the optimal allocation of water, the improvement of water resources utilization efficiency and the economic benefit of irrigated areas. © 2020 John Wiley & Sons, Ltd.

A combined optimization-simulation approach was used to develop and evaluate the alternate priority-based policies for operation of surface and groundwater systems and is demonstrated with a case study. An optimization model was used to find optimal cropping pattern with and without the conjunctive use of surface and groundwater, as well as with and without socio-economic constraints. The optimization model, based on linear programming, maximizes the net benefit from irrigation activities subject to various physical, economical, and social constraints. A simulation model was used to evaluate the conjunctive operation of the system using the optimal cropping pattern derived from the optimization model. The developed policies have been verified with long-generated stream flow sequences. Three alternate priority-based policies differing in level of groundwater pumping and area of cultivation of rice crop have been evaluated: (1) irrigation with surface water only (Policy-1); (2) irrigation with conjunctive use of surface and groundwater, without socio-economic constraints (Policy-2); and (3) irrigation with conjunctive use operation and with socio-economic constraints (Policy-3). It was found that the use of available groundwater within three meters below ground level (Policy-2) to be optimal, and these results were used in simulation for further evaluation of policies. It was also found that the policy-3 of conjunctive use operation with a priority of 75 percent of maximum possible rice area (using groundwater available within four meters below ground level) resulted in a better scenario. Thus the conjunctive use Policy-2 and Policy-3 with 75 percent of maximum possible rice crop area can be used as better policies for the system studied.

Conjunctive use of surface and groundwater is an effective approach to relief water resources shortages and its uneven temporal and spatial distribution in arid inland regions of central Asia. In this paper, 16 characteristic factors of water resources and related systems which are sensitive to different types of conjunctive use were selected in order to develop an index system for evaluation impact of conjunctive use, based on the fundamental types of water resources conjunctive use in inland basins. In an attempt to address the issue of spring drought and summer floods in Tailan River Basin in Xinjiang, three scenarios of conjunctive use of surface water and groundwater, well-canal combination, piedmont reservoirs and groundwater reservoirs were investigated. The utilization of water resources and the response of its related systems were evaluated and analyzed quantitatively using the groundwater numerical simulation model (Visual MODFLOW). Furthermore, the impacts of conjunctive use were assessed using the method of multi-level fuzzy comprehensive assessment. The results show that the scheme of combination of Laolongkou piedmont reservoir regulation-groundwater development, is the best in terms of the evaluation of water conjunctive use effects, followed by the well-canal combination. The comprehensive effect of well-canal combination along with groundwater reservoir wouldn’t be better than the former both.

This research presents alternate policy decisions based on technical strategies to operate minor and medium irrigation schemes with integrated conjunctive use of surface and groundwater to improve groundwater systems in Vavuniya area for the economic pumping for agricultural and domestic water use, by optimizing the use of groundwater and surface water. Forty one domestic dug wells were identified as observation wells among the available domestic/agro wells within the study area of 185.23 km2, to represent the aquifer in Vavuniya. This study area was divided into forty one Thiessen polygons. A complete water balance study for each polygon for each season was carried out. Water levels were predicted for changes in operational policy of minor and medium irrigation schemes by forgoing certain percentage of cultivation, boundary treatment to reduce the transmissibility in steps, and combination of both. The economic feasibility was analyzed by taking the energy saved in pumping of raised groundwater as a benefit and boundary treatment cost and income loss due to change in operational policy of minor and medium irrigation schemes by forgoing certain percentage of cultivation as cost. The present worth of benefit and cost for various interest rate and project life period were calculated and compared. Change in operational policy of minor and medium irrigation schemes by forgoing one third of the cultivation under them or keeping one fourth of the storage of minor and medium irrigation schemes at any time together with 40% -50% reduction in boundary permeability will recover an average of 60% to 70% of the loss of water table in any consecutive season in almost 95% of the area under consideration. ENGINEER, Vol. 46, No. 01, pp. 21-29, 2013

Conjunctive use of surface water and ground water is a complex water management strategy that involves management of surface water and groundwater as one resource under diverse geological, hydro-geological, hydrology and geophysical setting. India has adopted this concept as management strategy since 1970s, but the progress of the same hasn't been encouraging as on date. The strategy has been a setback in Indian context, despite prioritizing 40 years ago, due to the limitations and lacunae of research and institutions. The paper identifies the causes and impediments that has slowed implementation of conjunctive use of surface and groundwater in India and recommends measures to reset its strategy in the 21 st century.

Conjunctive use of groundwater and surface water is being adapted in many countries to enhance the intensity of irrigation and host at often benefits like cope with the water logging and salinity problems in canal irrigated areas, blending of water reduce the contamination load etc. In India, a number of scientific studies have been conducted which conclusively proved its importance and benefits, but the implementation of this technology has been overlooked because of apathy at various levels. The implementation of conjunctive use program has to be considered now seriously if we really mean “each drop of water counts” for food security in views of the climate change scenario. The chapter presents details of the different aspects of the conjunctive use with the assertion that institutional arrangements and action plan be made for taking up the projects for which detailed hydrogeological studies have already been completed and found favorable for its application.

Conjunctive use of surface and groundwater has received growing attention since the introduction of sustainable development of water resources. Cyclic storage system is an extension to conjunctive use of surface and groundwater in which the surface water bodies and groundwater aquifer(s) satisfy the prespecified demands in an interactive loop. Cyclical exchange of regulated water between groundwater aquifer and surface reservoir is the key element of a cyclic storage system that differentiates it from the conjunctive use of surface and groundwater systems as usually practiced. In the present study, reliability-based design of the cyclic and non-cyclic storage systems models is formulated as a multi-objective programming and intends to minimize the construction and operation costs and maximize the reliability of water allocation to the agricultural sector. Results show that the performance of cyclic storage system significantly improves by more efficient storing of surface water in a groundwater basin in wet seasons (years) and using it during dry periods. So, in order to fully meet the present demands in cyclic strategy, we had to pay just under 90.4 billion rials, compared to the non-cyclic strategy. It is also shown that, for any given cost, the reliability with cyclic strategy well exceeds that of non-cyclic strategy. In addition, the cyclic design of the system implicitly reduces the probability of flooding downstream significantly rather than the non-cyclic strategy.

Due to limited groundwater resources in arid and semi-arid areas, conjunctive use of surface water and groundwater is becoming increasingly important. In view of this, there are needs to improve the methods for conjunctive use of surface and groundwater. Using numerical models, optimization algorithms, and machine learning, we created a new comprehensive methodological structure for optimal allocation of surface and groundwater resources and optimal extraction of groundwater. The surface and groundwater system was simulated by MODFLOW to reflect groundwater transport and aquifer conditions. The important Marvdasht aquifer in the south of Iran was used as an experimental study area to test the methodology. In this context, we developed an optimal conjunctive exploitation model for dry and wet years using two new evolutionary algorithms, i.e., whale optimization algorithm (WOA) and firefly algorithm (FA). These were used in combination with the group method of data handling (GMDH) and least squares support vector machine (LS-SVM) to estimate sustainable groundwater withdrawal. The results show that the FA is more efficient in calculating optimal conjunctive water supply so that about 61% of water needs were met in the worst scenario for surface water resources, while it was 52% using the WOA. By applying the optimal conjunctive model during the simulation period, the groundwater level increased by about 0.4 and 0.55m using the WOA and FA, respectively. The results of Taylor's diagram, box plot diagram, and rock diagram with error evaluation criteria, i.e., root mean square error (RMSE), mean absolute error (MAE), and Nash-Sutcliffe efficiency (NSE), showed that the GMDH (RMSE = 6.04 MCM, MAE = 3.89 MCM, and NSE = 0.99) was slightly better than LS-SVM (RMSE = 6.36 MCM, MAE = 4.50 MCM, and NSE = 0.98) to estimate optimal groundwater use. The results show that machine learning models are cost- and time-effective solutions to estimate optimal exploitation of groundwater resources in complex combined surface and groundwater supply problems. The methodology can be used to better estimate sustainable exploitation of groundwater resources by water resources managers.

Study regionThe off-stream artificial Bar lake, built in 2015 to store the flood flows of the Bar river for domestic and industrial needs and with the objective to intentionally recharge the aquifer, is situated in the Razavi Khorasan province (Iran). Study focusWe present a methodology, based on the combination of a MODFLOW groundwater flow model for estimating seepage rates, and an optimization model, for the management and operation of an artificial reservoir considering surface/groundwater interactions for satisfying 12 Mm3/year of water demand. We simulated the reliable amount of water that can be supplied from the reservoir, considering reservoir seepage, maximizing water supply yields subject to the water supply reliability requirements, and the additional intentional volume of groundwater recharge. New hydrological insights for the regionOur results demonstrate the reliability of conjunctive use of surface-and ground-water in water scarce areas by exploiting reservoir infrastructures with relevant leakage losses, also for creating additional aquifer storage. In such systems, man-induced changes of lake stages can significantly affect the volume of water that seeps through the lakebed. The aquifer, under managed aquifer recharge operations, may then provide the resource not satisfied by the reservoir release, fulfilling 100 % reliability of water supply. The conjunctive use of surface- and ground-water, by improving water security, may open new sustainability views for leaking reservoirs, even if they were not initially designed for increasing aquifer recharge, in many areas worldwide.

Improving water security is critical to delivering the best outcomes for development. In Ethiopia, the upper Awash sub-basin supports expanding urban and industrial areas, with increasing water demands. Studies have preferentially focused either on surface water hydrology or on groundwater characterization. However, novel tools are required to support the conjunctive use of surface and groundwater for competing users under potential climate change impacts. In this paper, we present research based on a WEAP-MODFLOW link configured for four catchments in the upper Awash sub-basin (Akaki, Melka Kunture, Mojo, and Koka). The Akaki catchment supplies water for Addis Ababa city. Unlike most surface water hydrological models, both supply (surface water and groundwater) and demand (domestic, industrial, and livestock) are modeled. The tool was used to evaluate the impacts of population growth, leakage, expansion of surface and groundwater supply schemes, and climate change scenarios up to the year 2030. Considering the high population growth rate scenario for Addis Ababa city, the unmet domestic water demand may increase to 760 MCM in 2030. Water leakage through poor water supply distribution networks contributed about 23% of the unmet water demand. Though not significant compared with population and water loss stresses, climate change also affect the supply demand condition in the basin. Planning for more groundwater abstraction without considering additional surface water reservoir schemes will noticeably impact the groundwater resource, with groundwater levels projected to decline by more than 20 m. Even more groundwater level decline is observed In the Akaki catchment, where Addis Ababa city is located. Conjunctive use of surface and groundwater not only boosts the supply demand situation in the basin but will lift off some of the stresses from the groundwater resources. Even under the likely increase in temperature and low precipitation climate scenarios, the conjunctive use resulted in a significant increase in domestic water demand coverage from 26% for the reference condition to 90% in 2030, with minimum effect on the groundwater resources. To improve water security conditions through sustainable utilization of both surface and groundwater resources, policy responses need to consider surface and groundwater conjunctive use. Minimizing water leakage should also be given the highest priority.

Maximizing conjunctive use of surface and ground water under surface water quality constraints

We reviewed papers on optimal conjunctive use of surface and groundwater (GW) with application in dry regions. Selected papers from the last 25-year period were reviewed using the PRISMA method. We show that with increasing scarcity of water, objectives of models developed for optimal conjunctive use have become more environmentally and socially oriented. About two-thirds of the studies are dedicated to single-objective problems, while the rest are dedicated to multi-objective problems. More than 45% of the single-objective optimization models employed metaheuristic algorithms. Genetic algorithm and particle swarm optimization were the most popular algorithms. There are still many challenges in the optimal conjunctive use of surface water and GW resources. GW quality, which affects human health and the environment, is often not considered in optimization studies. Climate change and drought, as serious threats to the water supply, need to be more adequately addressed. Uncertainty in data and results is often not considered in such studies. Most importantly, there is usually no proper collaboration between various stakeholders, and thus, the level of satisfaction and benefit due to optimization approaches is still unclear. Water resources managers and decision makers need to be made aware of this approach, in which researchers can play more effective roles.

Developing operating rules for conjunctive use of surface and groundwater considering the water quality issues