Evaluation of Interaction between Aquifer and river Using Integrated SWAT-MODFLOW-NWT Model (Case study: Mahabad plain)

Surface and groundwater dynamically interact at different spatial or temporal scales within a plain. Accurate estimation of water balance components is an important simulation of such interactions. Despite the rapid expansion of numerical models over the past two decades, there is still room for improvement for comprehensive and integrated assessment as well as management of surface and groundwater resources. In particular, the use of coupled surface and groundwater models is important to connect both surface and groundwater, and for proper representation of the water balance in the unsaturated root zone. The results of various studies suggest that the combination of SWAT and MODFLOW models can satisfactorily simulate the interaction between surface and groundwater at different spatial and temporal dimensions (Sophocleous and Perkins, 2000; Sun and Cornish, 2005; Bejranonda et al., 2007). Indeed, if both models are used simultaneously, not only the limitations of the two individual models can be improved, but also the temporal-spatial properties of the target area can be adequately reflected (Kim et al., 2008; Park and Bailey, 2017; Wei et al., 2018). Specifically in the Urmia Lake Basin, which has been severely affected by indiscriminate exploitation of water resources, these models can be used to maximize the supply of Urmia Lake based on the pattern of supplying irrigation needs from integrated water sources. This requires the interaction of surface and groundwater resources in different locations of plains and aquifers to be simulated and predicted based on different shares of agricultural water supply from integrated water sources.The main purpose of this study was to evaluate the interaction between ground and surface water in Mahabad plain using the coupled SWAT-MODFLOW-NWT model as a comprehensive and integrated model. The main challenge in this study is the interaction and monitoring of water table adjacent to the surface water bodies

Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia

Lake Urmia is one of the largest hypersaline lakes on earth with a unique biodiversity. Over the past two decades the lake water level declined dramatically, threatening the functionality of the lake’s ecosystems. There is a controversial debate about the reasons for this decline, with either mismanagement of the water resources, or climatic changes assumed to be the main cause. In this study we quantified the water budget components of Lake Urmia and analyzed their temporal evolution and interplay over the last five decades. With this we can show that variations of Lake Urmia’s water level during the analyzed period were mainly triggered by climatic changes. However, under the current climatic conditions agricultural water extraction volumes are significant compared to the remaining surface water inflow volumes. Changes in agricultural water withdrawal would have a significant impact on the lake volume and could either stabilize the lake, or lead to its complete collapse

System Dynamics Modeling of Multipurpose Reservoir Operation

System dynamics, a feedback – based object – oriented simulation approach, not only represents complex dynamic systemic systems in a realistic way but also allows the involvement of end users in model development to increase their confidence in modeling process. The increased speed of model development, the possibility of group model development, the effective communication of model results, and the trust developed in the model due to user participation are the main strengths of this approach. The ease of model modification in response to changes in the system and the ability to perform sensitivity analysis make this approach more attractive compared with systems analysis techniques for modeling water management systems. In this study, a system dynamics model was developed for the Zayandehrud basin in central Iran. This model contains river basin, dam reservoir, plains, irrigation systems, and groundwater. Current operation rule is conjunctive use of ground and surface water. Allocation factor for each irrigation system is computed based on the feedback from groundwater storage in its zone. Deficit water is extracted from groundwater.The results show that applying better rules can not only satisfy all demands such as Gawkhuni swamp environmental demand, but it can also  prevent groundwater level drawdown in future

Siting Detention Basins Using SWMM and Spatial Multi-Criteria Decision Making

Detention basins are one of the structural measures for floodwater control in urban environments. They are effective tools in flood mitigation, but some studies have shown that they may aggravate the condition if not properly sited. This study presents an innovative approach which directly incorporates hydrologic-hydraulic modeling results to the site selection procedure for flood control detention basins. Darakeh Catchment located in Tehran is selected as the case study. Hydrologic, physiographic, and economic parameters are considered as siting criteria. SWMM model is employed for simulating hydrologic-hydraulic processes and evaluating the current drainage network against low-frequent storms. Modeling results, including flooded junctions and the flow hydrographs, are used as input parameters to the spatial decision making framework. The framework employs Analytical Hierarchy Process (AHP) as the decision making structure and geographic information system (GIS) as the spatial analyst tool. The output is a raster map which shows each cell potential for the placement of the detention basin. The proposed approach aims to improve the siting procedure based on these measures and other BMPs in an urban environment

A System Dynamics- Based Analysis of Operation Policies for Water Resources at River Basin Scale

There are many natural and human subsystems in a watershed with their special interrelationships. These interrelationships must be duly considered for the integrated and comprehensive management of the water resources in a water basin. One example of such interrelationships includes upstream water development and utilization projects which adversely affect downstream water quality and quantity. Within the framework of an integrated water resources management, various water resources development and operation policies must be analyzed to select the most convenient one securing the benefits of all the stakeholders in the watershed. In this study, various operation policies in theUrmiahLakeBasinand theAjiChaiRiverBasin on the east of the lake are analyzed to determine their impacts on the water level in the lake. For this purpose, the Aji Chai Basin is subdivided into three sub-basins and the System Dynamics, which is a feedback–based object–oriented simulation approach, is used to develop the dynamic model of the region. To investigate the present scenarios, the ARMA (1, 1) model is used to generate 10 different time series for each sub-basin and the lake water level is accordingly determined for each case

Assessment of Residential Water Conservation due to Using Low-Flow Fixtures

Increasing population and socioeconomic development have led to increased urban water demand. Residential use forms the principal portion of urban water consumption. One of the most effective residential water conservation measures is using low-flow fixtures and devices designed for this purpose. In this paper, conservation results of using low-flow fixtures including low-flow showerheads and faucet aerators are evaluated in the city of Kashan. For this purpose, two groups of 40 households were randomly selected as experimental and control groups. The fixtures were installed in the houses of the experimental group and water consumption was measured over one month. Results indicate that retrofitting with these fixtures reduces residential water consumption by about 22 percent. Projections of Kashan’s future water demand and supply indicate that using these fixtures by Kashan residents can delay the need for new water supply projects by up to 6 years. Cost-benefit ratio of this conservation measure for Kashan is estimated to be 5.8 to 1. Finally, user satisfaction of retrofitting with these fixtures is evaluated

A Method to Estimate Surface Soil Moisture and Map the Irrigated Cropland Area Using Sentinel-1 and Sentinel-2 Data

Considering variations in surface soil moisture (SSM) is essential in improving crop yield and irrigation scheduling. Today, most remotely sensed soil moisture products have difficulties in resolving irrigation signals at the plot scale. This study aims to use Sentinel-1 radar backscatter and Sentinel-2 multispectral imagery to estimate SSM at high spatial (10 m) and temporal resolution (at least 5 days) over an agricultural domain. Three supervised machine learning algorithms, multilayer perceptron (MLP), a convolutional neural network (CNN), and linear regression models, were trained to estimate changes in SSM based on the variation in surface reflectance and backscatter over five different crops. Results showed that CNN is the best algorithm as it understands spatial relations and better represents two-dimensional images. Estimated values for SSM were in agreement with in-situ measurements regardless of the crop type, with RMSE=0.0292 (cm3/cm3) and R2=0.92 for the Sentinel-2 derived SSM and RMSE=0.0317 (cm3/cm3) and R2=0.84 for the Sentinel-1 soil moisture data. Moreover, a time series of estimated SSM based on Sentinel-1 (SSM-S1), Sentinel-2 (SSM-S2), and SSM derived from SMAP-Sentinel1 was compared. The developed SSM data showed a significantly higher mean SSM state over irrigated agriculture relative to the rainfed cropland area during the irrigation season. The multiple comparisons (fisher LSD) were tested and found that these two groups are different (pvalue=0.035 in 95% confidence interval). Therefore, by employing the maximum likelihood classification on the SSM data, we managed to map the irrigated agriculture. The overall accuracy of this unsupervised classification is 77%, with a kappa coefficient of 65%

Assessing mountain block water storage changes in river basins using water balance and GRACE: A case study on Lake Urmia Basin of Iran

Study region: Lake Urmia Basin (LUB), northwestern Iran, encloses the largest salt lake in Iran, where severe drawdown of the lake water level is causing salt storms that threaten the health of the basin's inhabitants. Study focus: Different in-situ and RS-based datasets are used to estimate the water storage change (WSC) in LUB and partition it into the basin floor WSC and mountain block WSC components. Water balance components for LUB were estimated for the 2001–2011 period, using RS-based datasets for precipitation, actual evapotranspiration, soil moisture and snow storage. Ground-based data were used for validation of RS data as well as water balance closure purpose. GRACE terrestrial water storage data were also used to validate the water balance method results. New hydrological insights for the region: GRACE results confirmed an average WSC of − 921 million cubic meters per year (MCM/yr) (−17.6 mm over the basin area). WSC time series in the basin floor (average: −913 MCM/yr, or −53 mm over the basin floor area) was estimated by summing the related water storage components, and then subtracted from the basin WSC to estimate the mountain block WSC time series (average: −8 MCM/yr, or −0.2 mm over the mountain block area). To evaluate its authenticity, the estimated mountain block WSC time series was then compared to mountain block rivers’ base flow and springs' discharge, showing a considerable correlation between the time series. Considering the faster water resources depletion in the basin floor (where anthropological factors are significant) than in the mountain block (where anthropological factors are rare), one can conclude that anthropological factors may have the primary role in deteriorating water resources conditions in the basin

Conflict Resolution of Water Resources Allocations Using the Game Theoretic Approach: The Case of Orumieh River Basin

During recent years, unavoidable consequences of increased demand for, and decreased supply of, various natural resources, especially water, have caused increased conflict over their exploitation and also allocation to different stakeholders. Water allocations merely based on a water rights approach usually do not make efficient use of water for the whole river basin. Thus, there is a need for a comprehensive and stable allocation method that can satisfy all involved interest groups in the best manner. One of these methods is game theory that can be used to allocate the water resources among riparian parties regarding principles of equity, efficiency and sustainability. In this study, first a comprehensive linear programming model has been developed to achieve the optimal allocation pattern based on the initial water rights of stakeholders. Then, by using the results of the water planning model combined with the game theoretical concepts  such as the Core, the Shapely Value, and, the Gately propensity to disrupt index, possible cases of cooperation among riparian parties have been evaluated. Finally, through the case study of the Orumieh River Basin in Iran with scarce water resources and multiple users, effectiveness and potential advantages of this approach have been shown. The results of the optimization model showed that the Kordestan province has the best situation in supplying its demands relative to the other provinces and in contrast, the East Azarbayejan has the most deficiency in supplying its demands in both agriculture and environmental sectors. Moreover, by following the given allocation pattern, the amount of water entering the Lake Orumieh will be more than its environmental demand during the planning. Therefore, the results of this study showed that cooperative game theory can be applied successfully to assess the cases of cooperation in the Orumieh River Basin in conjunction with a comprehensive water planning model

Urban Water Management Considering Reclaimed Wastewater and Runoff as a New Water Resource for City of Tehran, Iran

Tehran, the capital of Iran, like many megacities in the world is faced with increasing freshwater demand and water resources limitation due to the rapid growth of population. In this paper, water reuse and wastewater recycling are considered as a sustainable solution for water supply and wastewater management of Tehran. A linear programming optimization model with the object of cost minimization is used to allocate water between users and resources, concerning the water quantity and quality of each one. Ultimately the economic and environmental effects of this strategy will be presented as the conclusion of this study. According to this study, improving wastewater treatment plants and control of water quality in canals and streams in order to substitute these two new resource for freshwater and groundwater have positive environmental and economic effects. The examples of environmental benefits are reducing pollution loads to receiving streams, adjusting increasing water demand and preventing groundwater level drawdown especially in the period of drought. In addition to the environmental benefits, although improving wastewater treatment plants and control of water quality in canals and streams need considerable investments, long usage of these two new recourses is more worthwhile