Dear Saeed,

we need to look for practices that make wet surfaces as small as possible.

- make use of self-mulching of drying soil surfaces where the wetness front gets away from the surface. This applies as soon as the surface is dry and evaporation further reduces when the dry layer of the soil increases;

- mulching of soil, naturally or artificially. An example is the natural availability of pebbles at the surface, that when dried make the evaporating soil surface smaller (Karnataka, India) or bringing pebbles to the surface in large quantities (growing of water melons in Ningxia Province, China) that reduce spring evaporation of autumn rain that fell through the pebbles (Case study in Stigter, Applied Agrometeorology, Springer, 2010).

- making evaporating water surfaces smaller in area, such as using sub-surface irrigation instead of sprinklers or furrow irrigation.

Of course for watershed management this need to be large surfaces for which these practices are applied. But the principle remains the reduction and/or the covering of evaporating surfaces.

Best wishes, Kees

1. For agriculture, in fruit garden, leaves or grass should be deposited near the roots of the plants and drip irrigation should provided. It can reduces the water evaporation in compare with open cultivated field.

2. If there is a small pond (may be agriculture pond, oil should be spread on the water so that there will be the layer between water and sunlight and evaporation reduces.

3. The structure of artificial pond (in India commonly refer as agri. pond) should be  wide in the upper part and gradually reduces its area at the center............................... please see the diagram attached

I am not clear whether you are trying to reduce evaporation from water surface or from the catchment basin in general. For water surface, you can increase the riparian vegetation and canopy cover. From ground surface you may have to consider evapotranspiration rather than evaporation alone. There are number of methods out there, such as mulching (as suggested earlier), drip irrigation, increased vegetation cover (but transpiration may increase), and you may also have to consider some soft path solutions such as what time of the day you irrigate the lawns, gardens, etc.

All the best.

Hello Saeed,

A detailed reply is not possible here but you may get your specific info from following link. 

http://www.fao.org/docrep/010/a1598e/a1598e02.htm

Water losses specifically from surface could be reduced by mulching on barren surface and reducing the surface area of water ponds.

Subsurface water application may significantly reduce the evaporation losses. The most forgotten part is selection of plant species, we have seen plant recommended for waterlogged area with higher ET were planted in water scares areas :)

Cheers.

The inherited know how of Tamil Nadu, India is the construction of temple tanks with steps on all the four sides, resulting in reduction of water spread area with respect to volume of water available.

The economy concern is the selection of choice of method. One can think of any vegetable non-edible oil with higher boiling point but will spread uniformly as a thin layer over water surface should be the better choice/ method.

If the pond is small, then you can think of shading/ covering the water surface with locally available materials, as is practiced in hills of North eastern states of India in structure called "Jal kund".

-ks

One should go for vegetative cover as much as possible to reduce the evaporation , on open water bodies certain chemical can be sprinkle to reduce evaporation

In the Canadian Prairies, back-flooding is done by raising the weirs to increase the area of infiltration and slow the flow during spring snowmelt runoff period to allow more time for infiltration into the soil. Ideally, it is better to recharge the groundwater rather than store in open reservoirs to minimize losses due to evaporation.  If dugouts are used to store surface runoff, then windbreaks are used to minimize evaporation due to wind.   The orientation of the dugout should be perpendicular to the major wind direction to minimize the evaporation.

Remember drop Irrigation used vastly in Israel and other countries nowadays. Yours, Ricardo Harboe

Dear all participants

Thanks for your useful answers. As you know, we need comparative assessment between results of application of mentioned practices in your answers to have a holistic decide about applicability of suggested alternatives in watershed scale (practices caused evaporation reduction). Are there any reported or documented results of applying discussed practices in your countries?

Dear Saeed,

examples of large scale mulch use are in

http://www.theicct.org/sites/default/files/publications/Teh_palm%20residues_final.pdf

https://books.google.co.id/books?id=pdsIAKwzm8oC

https://books.google.co.id/books?id=O9UqAAAAYAAJ

https://books.google.co.id/books?isbn=3110870274

Best regards, Kees

I am attaching an assignment presented in my class by one of my student from manipur state.

-ks

Dear Professor Stigter and Kumarasamy thanking you indeed for your all answers and attached files.

Saeed

The evaporation from the watershed can be reduced by following more vegetative covers, use of mulches, planting more no. of tree species and the water surface evaporation in water bodies can be checked by Cetyl Alcohol a chemical. 

dear Saeed,

an example of sand storage dam that can use to reduce evaporation in attached file

Best Wishes

Dear Ammar,

Thank you for the attached papers.

Saeed