نشریه آب و توسعه پایدار
سال هفتم شماره 2 (پیاپی 16، تابستان 1399)

The science of hydrology is the basis for decision-making in water resources management and assessing related risks including floods, droughts, and pollution. Despite its vital relevance to the society, this discipline is facing a severe shortage of data in appropriate spatial and temporal scales. This is especially true in low-income and underdeveloped countries due to lack of information and high cost of the monitoring process. Therefore, data collection by local communities and volunteers and monitoring through public involvement is considered effective in this regard. Citizen science entails the involvement of researchers and local volunteers in the process of data collection and analysis, scientific knowledge development, sharing information and encouraging interaction and responsiveness between local communities and natural environment. Literature review shows a limited number of social studies on hydrology and water resources, indicating low leaning to citizen science in water resources management compared to other disciplines such as ecology and astronomy, but there is an increasing trend due to increasing the importance of water resources. Results of researches show that if citizens are adequately educated, the reliability of collected data by citizens can be acceptable. Therefore, considering the potential of citizen science and use of technologies, the reliable, timely and long-term hydrological data can be obtained and used in decision making and management of water resources.

In Iran with an arid and semi-arid climate, the optimal use of water resources is a necessity. Due to the increasing population on the one hand and the reduction of groundwater resources on the other hand, quantitative assessment and calculation of the water balance of catchments are of great importance. Water balance reports are one of the most prominent study projects in water resources management in the country. Despite the importance of these studies, there are some issues in the process of preparation of water balances that may lead to errors. The purpose of this study is to evaluate water catchment balance calculations and identify the factors that cause the most uncertainty and error in these calculations. In general, the estimation of the water balance will be reliable, by reducing accidental and systematic uncertainties. These improvements can be achieved through the creation of a reliable data bank and turning it into an effective tool for balance assessment, as well as creating an adequate hydrogeology and hydrology knowledge of the study area, sufficient knowledge of the boundary conditions, an appropriate spatial and temporal resolution of the area, and accurate calculation of the input components such as rainfall, recharge, evaporation, irrigation status, and infiltration coefficients, etc.

The restrictions and challenges of renewable water resources and the increasing demand for water in different urban and service sectors, tourism, industry and agriculture have increased the significance and sensitivity of water resources management. This sensitivity is especially effective during the periods of dehydration. The experience gained in the past years regarding the water resources management has indicated that good management practices which are based on the principles of sustainability and increasing water productivity, reduce the challenges, constraints, and problems of water scarcity. In this regard, systematization of water allocation process is considered as a strategic strategy and a fundamental step to achieve water security and sustainable development of water resources. However, this system of water allocation in Iran has always been associated with problems (environmental issues, conflicts between upstream and downstream regions, etc.) that has been modified twice in 2003 and 2008. Despite the reforms and changes made in this regulation and method, we are witnessing the inefficiency of water allocation in Iran, because in order to achieve a favorable balance in the field of water supply and demand, as an important and essential principle in water allocation and sustainability, It will be possible only with a management that considers all dimensions (political, economic, social). As a result, the water allocation regulation in Iran is currently in need of amendments to determine the exact framework for water allocation and harvest control, in addition to considering the important goals of "water sustainability and productivity" in the water allocation regulation.

MENA region includes the heterogeneous group of countries with a range of high-income oil-exporting countries in the Persian Gulf to middle-income and lower-middle-income countries as well as least developed countries. It is regarded as one of the world's largest net food importers which faces significant uncertainties from supply and demand. According to the World Economic Forum, the water crisis is the most important challenge that the Middle East and North Africa are the least prepared to face. In this paper with a review approach, the major global hazards, water resources status, consumption and policies of agricultural water, water use productivity in agricultural production, climate change impacts on agricultural production and systems in the region, vulnerability of rain fed agriculture, classifying MENA countries by main water management challenges, possible types of interventions according to the agricultural system, and the status of countries' natural resources have been investigated. Based on the results, environmental protection strategies, water allocation and water service management approaches for the countries of the region have proposed.

There are several water storage reservoirs in different cities of Iran. These reservoirs are used to store irrigation water on agricultural lands. Improper use of water resources, pollution of water resources due to the entrance of urban and industrial wastewaters, as well as natural factors such as evaporation from open water surfaces, leads to available water losses. To reduce water evaporation from storage reservoirs and pools, several methods have been proposed such as using physical and chemical materials. One of the physical materials that can be used to control evaporation is floating covers of polystyrene sheets. In this study, the rate of evaporation reduction in the standard Colorado evaporation pan was investigated by adding 3 mm thick, 50 g/m2, 8000 Rials/m2 polystyrene sheets with 60% coverage. Results revealed that this material has proper function in controlling and reducing evaporation. By doing this test from June 2018 to September 2018 for 4 months in Semnan city, it was observed that polystyrene sheets could reduce evaporation by an average of 44%. Other advantages of this material include its cheapness, good durability against sunlight (about 3 years), water environment and no water contamination.

Due to the importance of water that is one of the first needs of human life and according to the problem that Iran has an average annual rainfall of 240 mm and its population of 80 million, It is a dry and semi-arid country, and it faces a lot of water stress, It is essential to prevent water loss as much as possible. One of these methods is the control of evaporation from water storage tanks, which is possible in different ways. Climate change on earth has also contributed to the cause, and the rate of evaporation has been increasing in recent decades. This can sometimes reduce more than 40% of the volume of water stored in the dam. This study introduces different methods and products of chemical and physical of evaporation control from the water surface and disadvantages and benefits of each. Finally, the methods were compared and prioritized using Analytical Hierarchy Process(AHP) in economic, executive, and environmental terms.

Excessive extraction of sand and gravel from the riverbeds entails many environmental problems. In this paper,the destructive environmental consequences of inordinate extraction of sand and gravel from the bed of the Nazlouchay river is investigated. Qualitative study and physical and chemical analysis of water of the Nazlouchay river at two sampling stations indicate the negative effect of sand and gravel mining activities, so that by increasing the amount of suspended particles from 20to98milligrams per liter,the amount of total solid suspended particles is quintupled, and consequently, the water turbidity in the second station has increased 14times. Excessive turbidity of the water of the Nazlouchay river and sedimentation of sludge in the lower bed as well as the instability of the riverbed due to sand and gravel extraction has caused the population of aquatic plants such as algae and macrophytes decrease sharply. even reach the brink of extinction. Other environmental consequences include: reduced quality of recreational, sportive, touristic landscape of the Nazlouchay river, bed erosion and river shore, and many other factors. Nowadays, the sand washing plant of the Nazlouchay with 1,800tons of daily feed consumes more than 1,650cubicmeters of fresh water,and produces about 1,500tons of screened sand and gravel. The wastewater of this sand washing plant with a solid content of about 10-15% is discharged into one of the extraction points site of the material as a tailings pond and sediment barrier.If the plant uses a Thickener system for water recycling by dewatering of its wastewater,the solid content of the waste output will be around 45%and the water consumption will be about 450cubicmeters, which will decrease to 27%of current water consumption. Also, if the paste tailing system is used in this plant, the water consumption will be only about 220cubic meters per day, which is only 13% of current water consumption.

Drawing upon five decades of experience in applying pollution control laws and programs, achieving water quality standards will never have been possible simply through the control of point sources. Designing discharge plans with the purpose of managing non-point sources along with point sources can be a solution to dealing with these conditions. As regards, recognizing the uncertainties in estimation of non-point sources pollution considered to be important. The market-based approach to transfer discharge permits between point and non-point sources and implementing it in the form of a proper market structure can be discussed as an efficient management tool in terms of considering inherent uncertainties of non-point sources as well as covering the shortcomings of the laws in this regard. These markets attractiveness would be increased due to the remarkable difference in marginal costs of pollution control of non-point sources with point. The inclination to participate in such a market can be increased by considering factors including the exchange type and optimized trade ratio. Besides, water quality trading market structures have a major role in the formation of exchanges between point and non-point sources. Possible structures to implement these markets include the stock market, bilateral negotiations and clearinghouses. Investigation into the main features of these structures in terms of market productivity and reliability of environmental efficiency indicates the inadequacy of the stock market structure between point and non-point sources. On the other hand, transaction costs and initial investments are key characteristics of the productivity of bilateral negotiations and clearinghouse market structures.

Each water resources system consists of several subsystems.These subsystems have intertwined and dynamic interactions and feedback.The reliability of water resource systems is usually maintained naturally. But the spread of human intervention in the last century has had a negative impact on water resources and jeopardized the reliability of these systems.Rules governing water abstraction and consumption now play an important role in the survival of water resources.In fact,the effectiveness of these rules and the compliance of the human sector(officials,plumbers,etc.)with it,can make the system reliable.But to improve a system(address shortcomings and improve effectiveness),management needs to evaluate its policies and strategies.Therefore, the evaluation system must be designed and implemented.But what is the meaning of evaluation system?This article tries to describe the organic relationship of the evaluation system(from data to decision)with management.It seems that in Iran today,the concepts and importance of measurement and monitoring should be emphasized and more than that,the principled role of this data in management.Because the evaluation system plays a vital role in the integrated management of water resources.The measured data must not only be reliable and sufficient,but also be tailored to management needs (at different levels).Therefore,this article addresses the issues of"sustainable development and water resources","plan and program for monitoring water resources and consumption",the role of criteria/indicators/indicators in the evaluation system",as a necessary tool in developing a purposeful evaluation system to increase The decision-making power of managers in the field of water resources has been addressed.In this way,the conceptual model of this evaluation system for water resources management is briefly presented.