ESTIMATION AND IMPLEMENTATION OF ENVIRONMENTAL FLOWS

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1 ESTIMATION AND IMPLEMENTATION OF ENVIRONMENTAL FLOWS Sharad K. Jain Indian Institute of Technology, Roorkee Global Water Systems Project 2011 Oct 18-20, 2011, Xian, China

2 INTRODUCTION Environmental flows are the quantity, timing, duration, frequency and quality of flows required to sustain freshwater, estuarine, and near shore ecosystems and the human livelihoods and well being that depend on them (Acreman & Ferguson, 2010). EF are necessary to maintain the health and biodiversity of downstream water bodies, including coastal waters, wetlands (mangroves, sea grass beds, floodplains) and estuaries. Besides the amount, one should also specify when this flow should be ensured. EF are one aspect in integrated water management.

3 Environmental Flows Krchnak et al. (2009): environmental flow refers to a variable water flow regime that has been designed and implemented such as through intentional releases of water from a dam into a downstream reach of a river in an effort to support desired ecological conditions and ecosystem services.

4 ESTIMATION AND IMPLEMENTATION OF EF - Data Related Issues In any EF study, data availability is a major limitation, particularly in developing countries. In addition to hydrology, data from sectors such as ecology, biology, environment, and social sectors are needed. Generally network of stations at higher altitudes is rather scarce. It is quite likely that measured river discharge, cross sections and flow velocity are not available at site of interest and have to be estimated from a distant station. Nearly two-third of surface water potential of India comes from the rivers that originate in Himalayas and there are very few river gouging stations at attitude above 500m. Thus, there is a real scarcity of data in these places. Data availability is a crucial bottleneck for Himalayan rivers.

5 ESTIMATION AND IMPLEMENTATION OF EF - Data Related Issues Data about water quality variables and aquatic species (their habitat requirements etc.) are collected at even fewer places and with much less frequency. It is generally not possible for the study team to launch a field campaign to collect the required data for a typical study. Limitation of data may constrain the choice of methods that can be applied. Visits to the study region, preferably in different seasons, are always helpful but cannot overcome the data deficiencies. Any global database of water quality and ecological databases??

6 ESTIMATION AND IMPLEMENTATION OF EF -- Water Quality of Environmental Flows EF will serve their purpose if, in addition to quantity, quality of water meets the desired standards. EF are not provided to maintain river water quality by dilution. In the end, what one may see in a river is not water but muck. In most of the studies, quality aspect is not considered and the same is true in actual implementation. This issue is important for many countries because many rivers are severely polluted.

7 ESTIMATION AND IMPLEMENTATION OF EF -- Reluctance by project proponents to release EF Rivers in mountain areas have steep slopes and these are good places to generate hydroelectric energy. No EF requirement was placed on projects that were built, say more than 30 years ago. EF for these projects may vary from 10 to 30% of MAF. Some operators of hydropower projects consider each unit of water bypassing turbines as loss; reduction in generation of energy due to EF may be up to 20%. There is reluctance by project owners to release water in river for environment, bypassing powerhouse. It is necessary to initiate dialogue put a mechanism to ensure compliance and give compensation. An automatic gauge recorder or involvement of local population in monitoring could help.

8 ESTIMATION AND IMPLEMENTATION OF EF -- Reluctance by project proponents to release EF

9 ESTIMATION AND IMPLEMENTATION OF EF -- Flashiness Induced by Peaking Operation Flashiness, or rate of change, refers to how quickly flow changes from one condition to another. Higher flashiness can be harmful to the aquatic life. Indices to describe flashiness: Q30/Q70 statistics Baker flashiness index is obtained by summing, usually over one year, the absolute values of the day to day changes in the average daily discharge values and dividing it by the sum of the average daily discharges. FI can be used to study the impact of flashiness on river ecosystem.

10 ESTIMATION AND IMPLEMENTATION OF EF -- Religious and Cultural Aspects of Rivers In many countries, rivers have great religious and cultural significance for a vast population. Some societies attach great cultural and religious importance to rivers, e.g., rivers are considered sacred and worshipped in India. Many important religious places are located on the banks of rivers. It is a common belief that a bath in Ganga river washes away all the sins. Similarly, Nile and Jordan rivers have religious and cultural significance. Water of many rivers is extensively used for social and religious rituals and they have a central place in popular customs and festivals. In the Hindu religion, some rituals are best performed by the side of a flowing river.

11 ESTIMATION AND IMPLEMENTATION OF EF -- Religious and Cultural Aspects of Rivers In the Hindu religion, some rituals are best performed by the side of a flowing river. Further, on auspicious days, large number of pilgrims assemble on the banks of rivers and ponds to take holy bath and at times the number of devotees may be in millions. Hence, governments have to ensure enough water of desired quality in the rivers, particularly on the auspicious days during the lean season. Further, there should be adequate depth of flow for people to take bath. Flow requirement for this purpose can be termed as Religious Flow Requirement (RFR). RFR is ensured by giving clear directions to the project authorities to release water.

12 ESTIMATION AND IMPLEMENTATION OF EF Special Problems of Alluvium Rivers In rivers flowing through highly permeable soils when water table is low, there can be substantial loss of water due to infiltration. Hence, while estimating EF, the loss of water in the river channel should also be considered. Special Aspects for Densely Populated Countries Per capita water availability is usually very low. Typically have low flows and rivers may be highly polluted. Withdrawal of water by directly pumping from the rivers is quite common although it may not be legally permissible. It is challenging to enforce actual EF provisions. Implementation becomes progressively more difficult as water stress increases. Therefore, enabling legal provisions have to be ensured for implementation and enforcement of EF.

13 CONCLUDING REMARKS An emerging challenge is to utilize water resource resources to provide sustainable social benefits while minimizing adverse impacts on natural ecosystem. Many of the adverse impacts on river ecosystems due to construction and operation of dams can be minimized by careful planning and operation. Ideally, environmental flow requirements should be estimated in planning stage of a project. It will be better and easier to integrate environmental considerations in the planning stages of new dams. Modifying the design and operation of existing schemes will be far more difficult and costly.

14 CONCLUDING REMARKS A program of monitoring, evaluation, and adjustment adaptive management should be fully and explicitly integrated into any water resources development plan (Krchnak et al. 2009). An urgent priority for many regions is on the quantification of relationships between hydrological and ecological indicators in rivers and creating baseline database of ecological information. EF depends upon the development stage of the region and what the society expects from the river. Many places have limited, dispersed, and un-organized data on relevant sectors such as environmental, social and biotic, particularly true for mountain regions. Overcoming data limitations and consultations with all the stakeholders is important in estimating EF.

15 Thank You

THE BRISBANE DECLARATION (2007)

THE BRISBANE DECLARATION (2007) Environmental Flows* are essential for freshwater ecosystem health and human well-being This declaration presents summary findings and a global action agenda that address