Shri Ram Karan

One way is to have a series of sedimentation tanks along the upper path of the effected lakes, up stream, so that the sediments can settle & clear water can pass through into the lakes in question. Water entry can be blocked in these tanks when the accumulated sediments has reached a level when it can be removed from it, so that they can be used again.

A second way is to broaden the entry point of water into the lake,so much so that when the speed of water entering the lake is very minimal,the sediments in question will settle beneath the very slow moving waters, & then they will not enter the lake in question.

A third way is to place series of metal trays suspended at an appropriate depth away from the bottom, with fish varieties like the Tilapia, so that as the fish has the habit of disturbing the bottom,the sediment will be disturbed, & some of it will settle on the trays, which needs to be periodically cleaned.

These are good suggestions when modeling is on proto scale I want the answer if we can go for the bathymetry survey taking lake itself on full scale as a system for modeling.

Sri Ram Singh,

If you want to go through the bathymetry route, here's one more suggestion:You can place a number of perforated pipes horizontally touching the bottom length wise,especially where the deposition rate is higher & through pumps lift up the water, which will be accompanied by the deposits.In this way sediments which bring about lessening of depth of the lake can be removed out of the lake in question.

Dear Ram Karan,

I am running such a numerical model with high resolution in time and on the vertical, built-in internal seiching and an approach to account for deep-water formation via littoral cooling in autumn. Maybe that the latter is irrelevant for african lakes. But seiching surely not. We have applied it successfully to various freshwater reservoirs in the mountains, to shallow and also to deep lakes. A special case was the North Sea ..

Your general problem is possibly that taking a model and feeding it with local data is already a challenge, but not sufficient to find an optimized answer. I just wrote in a final report for a certain Mekong project is that these inland-water problems are so complex that there are in general no universal solutions, and namely no cook-book solutions. What is needed for a serious approach is a co-operative multi-disciplinary research of a larger team of scientists and engineers included from the beginning, with a good educational component (somebody needs to do the work ..). And typically local measurements are needed, the physical and financial characteristics of which you only learn during the project.

Dear Helmut,

Thanks for the input your suggestions has given very insight feeling of the problem it will be very helpful.

Regards,

Ram

Your're welcome! HZB

Are the waterbodies in question lakes or reservoirs? If they are naturally formed lakes with rivers possessing a stable sediment load in balance with the watershed, then the normal successional progression of small lakes is to fill with sediment and transition to bog and then meadow. If the sediment load in the stream is the result of anthropogenic effects (over grazing, unsustainable forestry practices, agriculture, etc.), then you cannot fix the reservoir without fixing the problem. I can tell you from experience, the cost of continued dredging or sediment removal will far exceed the economic benefit you receive from the reservoir.

To solve the sediment loading problem, look at stream channel restoration and sediment models like:

Revised Universal Soil Loss Equation (RUSLE)

Watershed Assessment of River Stability and Sediment Supply (WARSS)

http://water.epa.gov/scitech/datait/tools/warsss/about.cfm

POWERSED and FLOWSED

And I would suggest reading up on Natural Channel Design http://water.epa.gov/lawsregs/guidance/wetlands/upload/Natural_Channel_Design_Checklist_5_16_12.pdf

http://www.bae.ncsu.edu/programs/extension/wqg/srp/guidebook.html

For lake and reservoir water quality monitoring models, you may find use for the Army Corps of Engineers' model CE-QUAL-W2.

Thanks Amanda,

I will see the possibility of using suggested model with primary data and its validation.