Dear Anand dev,

First of all I appreciate for such types of work in ecology & Environments,For construction of small dam for conservation of water and ecological Balance 

Proper planning of dams requires a heightened awareness of our natural and human environment. Concern for environmental quality includes concern for the air and water, our natural ecological systems, and our cultural resources. Many laws and regulations now reflect this concern and require the consideration of environmental factors in planning.

General categories of resources that should be considered include air quality, water quality, prime and unique farmlands, wild and scenic rivers, endangered species, wetlands, unique natural areas, wilderness areas, sound quality, visual quality, and geologic formations.

Experience in Federal water resources development indicates that fish and wildlife resources may represent a major portion of the environmental concerns that should be addressed before project construction and operation. These resources include animal species with economic importance because of their uses as food and for commerce, species with recreational importance because of their uses in hunting and fishing, and endangered species with ecological importance because of the concern for their protection. Species that are indicators of environmental health and species with esthetic appeal should also be considered.

Impacts to fish and other aquatic life resulting from the construction of a dam and subsequent impoundment of water can be caused by the change from flowing to standing water conditions, by the modification of downstream flows, by changes in temperature and water quality conditions, or by the addition of physical barriers to both upstream and downstream movements.

The effects of proposed design and operating criteria on the water quality should be evaluated both in the reservoir and downstream. Various tools are available to perform some of the required analyses. One of the basic factors that affects most water quality parameters is the temperature regime. Fortunately, fairly reliable temperature simulation models are available to predict temperature profiles in reservoirs . From the temperature simulation, it is possible to determine the time of initial stratification, the strength of the thermo cline, and the temperature profile.

generally acknowledged that, if access is available, a reservoir will be used for recreation. Water attracts people as a recreation medium (e.g., for fishing swimming, , and boating) and as a general feature of the area that enhances other activities, such as picnicking, camping, and sightseeing. In the planning and design of a reservoir, every effort should be made to maximize recreation benefits in a manner consistent with other project purposes. In most instances, recreation is not a major purpose of small projects, but can make an important contribution to overall benefits. 

For detail design and dimension please find attached herewith popular Book Design of Small Dam.

regards,

Prem Baboo

Popular book and free to download, Design of Small Dams. The book by Houlsby is specifically for grouting and water tightness issues.

You can find real data about cut off wall in my paper here.

Thanks

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