Vol-7, Special Issue-Number4-June, 2016, pp578-585 http://www.bipublication.com
Review Article
A Review on Principles and Methods of Determining the Environmental Water
Requirements in Iran
Leila Halajian, *Reza Arjmandi, Jamal Ghoddousi and Amir Hessam Hassani
Department of Environmental Management,
Faculty of Environment and Energy,
Science and ResearchBranch,
Islamic Azad University, Tehran, Iran
*Corresponding Author: Reza Arjmandi
ABSTRACT
In Iran, limitation of water resources is natural due to arid and semi-arid climate, therefore, studies to determine the environmental water requirements have been considered as a necessity in recent years. Environmental flow is one of the most important environmental parameters that should be carefully considered in agricultural water development planning studies. Water resource development projects, especially dam construction and inter-basin transfer of water, are occasionally inevitable due to lack of water and poor spatial and temporal distribution of precipitation. Environmental water demand assessment methods were developed to stabilize environmental flows, the protection of ecosystems or save a particular species (endangered). Methodology approaches in general is divided into two groups: prescription and interactive. Prescriptive approach usually addresses a certain goal and suggests the value of the individual or the individual flow regime. Interactive approach focuses on the relationship between changes in the river (or runoff). Prescriptive approaches include four groups: hydrological index, hydraulic ratio, habitat-simulation, comprehensive approaches. Assessment methods of flow with interactive approach are more complex than prescriptive methods and often include habitat simulation and holistic approaches. The most widely used environmental assessment method is hydrological index (prescriptive). In Iran, due to the lack of complete information regarding the characteristics of aquatic ecosystems and patterns precipitation in any area or the state of underground aquifers, and considering that people in many regions of the country (especially away from the center) are dependent on the river for their livelihoods, the assessment should also include socio-economic considerations. So, technical and economic feasibility should be considered for projects that require inter-basin transfer as water rights for future.
Keywords: environmental flow, water rights, water requirement assessment methods, Iran.
INTRODUCTION
Water is no longer considered as infinite and abundant blessings and the restriction of freshwater resources has become a serious problem in many countries. Governments and researchers and experts in this field have recognized the need to maximize the utilization of water resources with minimal loss and waste and consider water resources management as part of planning for the development of their countries.
that many countries have faced a serious crisis due to the shortage of water resources and other countries will also face this problem due to population growth and economic and social development, water system problems in the future will undoubtedly become more and more important. According to the calculations of the UN Commission on Sustainable Development, Water demand growth in 2025 will be equivalent to 212% of the demand in 1990. Thus, the need to consume water will be more than the water resources. In such cases, we will be forced to use water resources more appropriately (Omani & Chizari, 2011).
International Water Institute has predicted water shortages in 2025 for the 45 countries. The results of the study have led to the division of the countries into three groups: The first group consists of countries faced with physical water scarcity in 2025. This means that even with the highest possible efficiency and productivity of water use, this group will not have enough water for its needs. About 25 percent of the world, such as Iran, is included in this group (Montero & Francisco, 2005). The second group includes countries with no physical shortage. These countries are not currently faced with the water shortage, but they will need about 25 per cent more water in 2025. The third group includes countries that face economic water shortages in 2025.These countries have enough water to meet their needs in 2025, but they have to increase their water resources at least up to 25% compared to 1995 by the construction of dams and paying high costs. Many countries in this group are experiencing funding problems and will be faced with the dilemma in the water supply (Muralidharan, 2008).
Iran is located in the arid and semi arid climatic zone of the world. The average annual rainfall is 250 mm, which is much lower than the average rainfall of Asia and the world (732 and 831 mm).
Average precipitation in Iran is about 400 billion cubic meters per year that 270 billion cubic meters are evaporated and 130 billion cubic meters per year are used as renewable water. Water consumption in 1996 was equal to 86.8 billion cubic meters per year; More than 90% of which was related to the agricultural section and 7% was related to the industrial and drinking section. The total water consumption in 2001 was 1.93 billion cubic meters equal to the consumption in the areas of agriculture, industry and drinking in 1996 (Fiorillo et al., 2007). According to the current trend and assuming constant per capita water consumption and predicting 90.4 million people in 2021, 130 billion cubic meters of water will be needed. It is obvious that supplying this amount of water from renewable sources of water in Iran will not be possible and shortages and degradation of water resources are considered as an important challenge for Iran's development programs, and the challenge will be tougher in the future (ibid.). Hence, today inefficient water management is one of the main problems for agriculture, industry, and municipal consumptions in developing countries. The results of several studies suggest that water resource management is faced with technical, socio – cultural, and economic limitations, will lead to many adverse consequences (Ortega et al., 2005).
Water scarcity leads to poverty and the destruction of pastures and vegetation and economic, social and environmental damages. Also, besides the irreparable harm caused by the lack of water in agriculture and manufacturing, environmental issues should also be added because the effects of drought and water scarcity are irreparable and irreversible (Husary et al., 2002).
Location, precipitation regime, the amount of rainfall received and temperature conditions lead to the arid and semi-arid climate in Iran. Some of the country's natural and human geographical features are presented in Table 4.1.
Table 1: Some geographical features in Iran
Extent 1648195 sq. Km. share of semi-arid areas 20%
Population 77 million share of moist and
mean Precipitation in Iran 250 mm Distribution of precipitation 75%precipitation in 25 percent of the area mean Precipitation in the
world 860 mm. Temperature range
From -20 to 50 ° C
Population Ranking in the
Middle East Second total renewable water
130 billion cubic meters (per year)
Population ranking in the
world seventeenth
Total returned water consumption
29 billion cubic meters (per year)
Dominant precipitation
regime Winter
Renewable water per capita
in Iran 1670 cubic meters per year
mean temperature
throughout the day in Iran 18 degrees Celsius
Renewable water per capita
in the world 6500 cubic meters per year
mean temperature in the
world 15 degrees Celsius
Per capita renewable water in the Middle East and North
Africa
6500 cubic meters per year
Volume of annual rainfall 413 billion cubic meters area of regions below
precipitation mean
61 percent of area the country
Share of arid regions 65 percent (Less than 250 mm per year)
(Nasrabadi, 2015)
In the countries with this climate, shortages and scarcity of water resources are common, but it does not mean that the current situation of water crisis is due to normal conditions, but also it is due to human factors. Although the features of quality and quantity of water are associated, the separation of them is not simply possible. In a general classification, water crisis in Iran can be studied in two stages based on quality and quantity. The causes of water scarcity in Iran include imbalance of rainfall in the country, natural phenomena and drought, reduced water quality, competitive applicants and distressed investing and financing (Mahmoudi, 2004); natural barriers of structural, legal problems, problems due to unplanned exploitation and development of irrigation water and low yields (Khazai & Ali, 2004) excessive use, and so on (Mobini Dehkordi, 2004). Thus, studies to determine the environmental water requirements in Iran have been considered as a necessity in recent years. In 2005, a memorandum of understanding was signed between the Ministry of Energy and the Environmental Protection Agency. According to this memorandum of understanding, environmental requirements rivers of water resources development projects should be determined, leading to changes in the natural flow of rivers of the region. According to reports on Water Comprehensive Plan, determining
environmental water rights is mainly considered using hydrological methods. However, the compatibility of methods with the climatic conditions and ecological status of aquatic ecosystems should be studied. Accordingly, determining the environmental requirements of downstream water resources is one of the major studies and many efforts have been made to estimate the truth environmental requirements in recent years (Nouri, 2014). Hence, this study aims to review the principles and methods of determining the environmental water requirements in Iran.
Theoretical Foundations of environmental flows
frequency of flow ". In the other words, the flows which provide conditions for the maintenance of a variety of aquatic habitats and ecosystem processes are called "environmental flows". Environmental flows depend on the quantity and quality of the inputs and outputs and features of Basin (Smakhtin, 2004). A catchment area is defined as a land surrounded by highlands; so, runoff from rainfall has focused on the deepest point of the catchment area. In other words, the catchment area is where the surface runoff is naturally led to the point of concentration. If the point of concentration is located inside the basin, it will be called an endorheic basin, like Iran's central desert that the surrounding mountains have created a large block basin. A closed drainage basin retains water and allows no outflow to other external bodies of water. If the point of concentration is located at the end of the basin and the water can flow from that point, it will be called open basin (Ortega et al., 2005).
Physical characteristics of catchment area can be divided into two general groups: topography and permeability. These two characteristics are the factors affecting runoff and flooding. Characteristics of topography include basin level, slope, and drainage pattern. Characteristics of permeability include ability to attract water into the soil and storing moisture in it. Factors influencing the hydrological catchment area include (Tharme, 2003):
1. Geometric characteristics of catchment area include area, circumference, shape, position, channel length, mean waterway slope and river network density.
2. Soil characteristics of catchment area include hydrologic soil type, soil particle distribution, Texture and structure, erosion and permeability. 3. Vegetation: vegetation type of catchment area, distribution of vegetation in terms of evapotranspiration.
4. Hydrological characteristics: surface maintainability and groundwater.
5. Geological characteristics: Type of rocks, crevices and cracks, faults and fractures.
6. Climatic characteristics: temperature, type and amount of rainfall and the frequency of the occurrence.
7. Sediment load: Erosion, transport and deposition, degradation and sediment of catchment area.
8. Human factors: agricultural operations, animal husbandry, road construction, utilities and so on. Although factors 2 to 8 have a very significant impact on the volume of runoff and flooding characteristics, but the geometric characteristics of catchment area are effective in the discharge of catchment area. Geometric characteristics of catchment area include physical factors having relatively stable values and indicating the appearance of the catchment area. These factors are important because there is a correlation between them and runoff. They can be used to estimate the amount of runoff and the intensity of floods. Geometric characteristics of catchment area called Oro-hydrography include area, perimeter, main channel length, the shape of catchment area, width, slope, height, and time concentration. These characteristics are also called morphometric factors of the catchment area (Crowder & Diplas, 2000).
The most important input of environmental flow is precipitation. Precipitation is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail. It is the primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth. Most precipitation falls as rain. Evaporation and infiltration can be considered as important factors for the output of the catchment area. Increasing demand for water consumption will lead to increasing allocation of resources, ultimately resulting in environmental flows and affecting the ecosystem. The most important factor influencing the amount of water allocation is the resident population in the catchment area (King et al., 2000). Thus, it is necessary to define other terms related to the catchment area (Tharme, 2003):
movement of water on, above and below the surface of the Earth. This cycle include five main components: precipitation, infiltration, evaporation, evapotranspiration, runoff and groundwater flow was established.
Water right: it refers to the right of a user to use water from a water source, e.g., a river, stream, pond or source of groundwater.
Water allocation: In a hydrologic system in which there are multiple uses or demands for water, the process of measuring a specific amount of water devoted to a given purpose or use.
Water resource management: it is the activity of planning, developing, distributing and managing the optimum use of water resources. It is a sub-set of water cycle management. Water resources management has three stages: The first stage focuses primarily on water supply and is called supply management stage. The second stage is simultaneous management of supply and demand. In the final stage, all constructions are done for the extraction, transport, and distribution of water. The demand management stage is considered as the main task of the water management.
Water comprehensive law of Iran: According to this law, ministry of energy is in charge of national water management. The main tasks of ministry of energy to apply the national water management are as follows (Institute of management research and education, 2012): 1. Supplying the needed water for kinds of consumption
2. Containment of the floodwaters and storing the river water in surface or underground reservoirs. 3. Planning, allocation, and distribution of water by constructing irrigation networks, drainage, irrigation facilities and canals, pipelines, and channels 1 and 2 for dredging.
4. Protection, recovery, and beneficial use of underground and mineral water.
5. Preventing salinization of fresh water and desalination of salt water if necessary.
6. Cloud seeding
7. Monitoring the quality and quantity of water resources and uses
8. Water rationing in dry and arid regions in coordination with other concerned agencies 9. Investigating water resources and transboundary water
10. Revitalization and sustainable use of water historical structures in the country's water programs
11. Inter-basin transfer of water from the perspective of sustainable development and meeting the different consumer needs
12. Protecting and organizing rivers
13. Purification of wastewater In order to reuse.
Methods for determining environmental water requirements
Environmental water demand assessment methods were developed to stabilize environmental flows, the protection of ecosystems or save a particular species (endangered). Environmental water requirements of vital measures to protect surface water flows and water supply is required for a
variety of uses.
Methodolo gy approaches in general is divided into two groups: prescription and interactive. Prescriptive approach usually addresses a certain goal and suggests the value of the individual or the individual flow regime. Interactive approach focuses on the relationship between changes in the river (or runoff). Prescriptive approaches include four groups: hydrological index, hydraulic ratio, habitat-simulation, holistic (comprehensive). Prescriptive approach usually addresses a certain goal and suggests the value of the individual or the individual flow regime. Assessment methods of flow with interactive approach are more complex than prescriptive methods and often include habitat simulation and holistic approaches. The most widely used environmental assessment method is hydrological index (prescriptive) (Tharme, 2003).
different results are achieved from different ecological and hydrological conditions.
2. Tessman: This method is based on hydrological data and is an improved method.
3. Flow-duration curve: it is a cumulative frequency curve that shows the percent of time during which specified discharges were equaled or exceeded in a given period. it is another means of representing stream flow data combining in one curve the flow characteristics of a stream throughout the ranges of discharge. The flow-duration curve applies only to the period for which data were used to develop the curve or to the period to which the curve is adjusted.
4. Smakhtin: this method is used for assessment at the primary level and at large spatial scale. In this method, Environmental flow requirement is considered as a combination of low flow rate (LFR) and high flow rate (HFR) (Smakhtin, 2004).
5. Change of flow duration curve: It is a modified method of flow duration curve that will be different for each catchment area.
6. Range of variability approach (RVA)
7. Average Base Flow: Base flow is the component of stream flow that can be attributed to ground-water discharge into streams. The Base Flow Index (BFI) is the ratio of base flow to total flow, expressed as a percentage.
8. DRM
9. Water quality (Q): Q is the flow rate of rivers and can be used in two forms: 10 percent of Q90 that is actually 90% probability of occurrence and 10 percent of the flow rate for each of the months of the year. It is applied as its ecological flow of the river. The second one is 20 percent of Q90 that is actually 90% probability of occurrence and 20 percent of the flow rate.
10. French Fisheries Act: it is used for administrative approach of dam constrution in France, which is necessary to protect aquatic life. 15% of the average annual flow is considered for this method.
11. Montana: 10 to 20% of the average annual flow is considered for the month of October to the
end of March, and between 30 to 40 percent of the average annual flow is considered for the first of April to the end of September to provide good quality for aquatic life.
12. Texas: This method is based on hydrological data and the mean (or median) to drainage water (runoff) or percentile curve (King et al., 2000). Environmental water requirement is measured by using hydraulic through hydraulic variables such as wetted perimeter or maximum depth and assuming the integrity of the cross-section of a waterway. Habitat simulation method has been developed based on the hydraulic methodology. This method is a combination of habitat physical models (such as depth, viscosity, etc.) and its biological responses (optimal conditions and criteria for target organisms). The most important methods of this group Include PHABSIM and CASMIR that focus on aspects of the river ecosystem (Zhang et al., 2006).
Holistic method was developed in the 90s, and is also known as the building blocks method. This method requires the use of all aspects of the river ecosystem, including all aquatic and biota organisms (from source to mouth), especially endangered species. Relations between the water flow (monthly or flood), aquatic organisms, waterway status, sediment and water quality, sediment transport status (sediment rating curves) and pollution emission determine the holistic relations. The first step in holistic methods is estimating biota status for the population of target organisms. The most important methods of Texas Water Development Board include (Texas Water Development Board, 2012):
Blocks census data: This method can be evaluated by applying Geographic Information System to provide population distribution.
Utility residential connections: it is calculated based on annual population.
Multi-family population estimate: This method is appropriate for annual estimates and has a simple application.
methods, and also interactive methods suggests annual average flow rates in different conditions and seasons. Based on the principles of river water balance, regional water requirements can be made by water demand of the upper part and estimated on the basis of the lowest rate of discharge. If we examine the function of several rivers, we will find that the minimum monthly total water requirement is equal to total annual minimum water requirement. It is also needed to have at least one of the data related to flood conditions which defines the maximum rate to be more precise about the status of the annual discharge (Zhang et al., 2006).
CONCLUSION
Environmental flow assessment should contain a blend of different tools, such as environmental assessment and water sharing plan to guide decision goes towards sustainable development and optimization of water resources. Conservation of aquatic ecosystem in a manner consistent with its nature needs to be recognized and can be achieved by establishing water rights. In order to maintain a range of services and goods at an optimal level, a level similar to the condition of the ecosystem should be preserved. Ecosystem conditions are defined by the flow patterns, water quality, and structure of river. In Iran, due to the lack of complete information regarding the characteristics of aquatic ecosystems and patterns precipitation in any area or the state of underground aquifers, and considering that people in many regions of the country (especially away from the center) are dependent on the river for their livelihoods, the assessment should also include socio-economic considerations. So, technical and economic feasibility should be considered for projects that require inter-basin transfer as water rights for future.
REFERENCES
1. Crowder, D.W. and Diplas, P. 2000. Using two-dimensional hydrodynamic models at scales of ecological importance. Journal of
Hydrology, 230: 172-191.
2. Fiorillo, F., Palestrini, A., Polidori, P., & Socci, C. 2007. Modeling water policies with sustainability constraints: A dynamic accounting analysis, Ecological Economics, 63(2-3): 392-402.
3. Husary, R.S., Al’Sanah, W., Smith, M. 2002. Water access and storage as tools for integrated rural development, case study in the south of Hebron Region, Palestine Hydrology Group. 4. Institute of management research and
education, 2012. Water comprehensive law of Iran (Draft). Power Ministry, Islamic Republic of Iran. 29 P. (In Persian)
5. Khazai, A., Ali, M. I. 2001. Assessment of water sources condition in Zahedan basin. Human Sciences of Sistan & Balochestan, Geography (special issue) 70-92. (In Persian) 6. King, J.M., Tharme, R.E. and Villiers, M. De.
2000. Environmental flow assessments for rivers:manual for the building block methodology.
7. Mahmoudi, S. 2004. Water management, Sustainable development, National Agency of Sustainable Development. 11: 27-32. (In Persian)
8. Mobini Dehkordi, A. 2004. Accomplishment of supply management and demand of water, Appropriate solution for water crisis and challenge in future, Journal of Agriculture and Natural Science Engineering. 1(2): 54-59. (In Persian)
9. Montero, R. J., & Francisco, B.R.A. 2005. Land and water use management in Vine growing by using geographic information system in Castilla–La Mancha, Spain, Agricultural Water Management, An International Journal, Elsevier, 77(1-3): 82-95. 10.Muralidharan, D. 2008. Microeconomics of
water management: spatial dynamics and sustainability, Ph.D dissertation in economics, University of California, Riverside.
(In Persian)
12.Nouri, J. 2014. Localization of resistance condition of Ecohydrologic by integrated methods SMCE and CEQUALW2 (The case study: Latian dam, Tehran province), Azad University Research Project, 177 P. (In Persian)
13.Omani, A., Chizari, M. 2011. Identification model for prediction of sustainable management of agriculture water acceptance within wheat farmers of Ahvaz. Agricultural Economic and development. 19(73): 77-100. (In Persian)
14.Ortega, J. F., De Juan, J.A., & Tarjuelo, J.M. 2005. Improving water management: The irrigation advisory service of Castilla-La Mancha, Spain, Agricultural Water Management, An International Journal, 77(1-3): 37-58.
15.Smakhtin, V.U., Revenga, C. and Doll, P. 2004. A pilot Global Assessment of Environment Water Requirement and Scarcity; International water Resources Association: pp307-317.
16.Texas Water Development Board, 2012. Guidance and methodology for reporting on water conversation and water use. Texas Commission on Environmental Quality 17.Tharme, R.E. 2003. A global perspective on
environmental flow assessment: Emerging trends in the development and application of environmental flow methodologies for rivers, rivers research and application, pp. 397- 441. 18.Zhang, Y., Yang, Z. F., Wang, X. Q. 2006.
