The model includes parameters that can be influenced by acommunity to manipulate water quantity. The amount of water is specified as afunction of parameters that influence infiltration as, Q_w= f(V_g,Vf,V_sh,D_i,S_t), where V_g, V_f,and V_sh, are the proportion of the watershed under grassland, denseforest cover and shrubs respectively. D_i is the vegetation diversityindex of the area while S_t is the soil type of the watershed area.The vegetation parameters V_g, V_f, and V_sh, aredefined in terms of (1,0) where the variable is equal to 1; if the proportionof the catchment has 20% of its area under dense forest or shrub and if thegrass area is greater than 50%. It’s important to survey more than onehousehold in the catchment area so as to obtain a good estimate of the adequacyof the water.

The general model for the ECA’s landscapes is given as: Waterquantity = -0.06+0.7St – 0.005 V_g+0.047V_sh + 0.06V_g+ 0.21D_i. This innovation was developed in 2011 in Kenya.

The ultimate beneficiaries of the innovation are water users,farmers, NGOs, CBOs and PES institutions. The innovation is ready forup-scaling, although it has not yet been released for public consumption. The innovationwas tested in Mt. Elgon landscape in river watersheds where the proportion ofvegetation types in the watershed were compared to the water quantity in therivers originating from the watershed.

The model is a vital tool in attribution of watershed managementbenefits or outcomes to specific land management practices in a particularwatershed. This model is gender neutral and can potentially increase amount ofwater in landscape for agricultural and domestic use in the landscape. ThisTIMP can be implemented to increase amount of rain water stored foragricultural and domestic use in the landscape.

In contexts where there are PES arrangements in place, the modelcan be financially beneficial to land users/suppliers of watershed managementas an ecosystem service.

The model for valuation of landscapesfor watershed management is gender-neutral. Its application is equally usefulto all gender categories.

Anderson Kipkoech;

Lead Scientist, International Centre for Insect Physiology andEcology (ICIPE);

P. O. Box 30772;

Nairobi, Kenya.

Email: akipkoech@icipe.org

Adano W. Roba;

Lecturer, Moi University;

P. O. Box 333-60500;

Marsabit, Kenya.

Tel: +254-0202656947

The forest functions related to watershed management are importantto communities in the East and Central Africa (ECA) region where rainfall ishighly seasonal, generally limited in quantity and poorly distributed.Availability of water for agricultural production and domestic use inproductive landscapes depends on the ability of the landscapes to store therainwater for continuous use as rivers. It is expected that the amount of waterthat trickles out as rivers is directly related to the amount of infiltratedwater, i.e., water volume in the river = f (water infiltrated). We can thusmanipulate the parameters that influence water infiltration in order to achievethe desired water quantity. The communities living in the mountainous areas ofECA cannot measure the volume of the daily water demand. Therefore, a usefulmodel that can be used to implement Payment for Environmental Services (PES)should include parameters that can easily be interpreted at household level.Water volume can be represented on a scale of 0-1 with 1 representing adequatewater and 0 representing inadequate water. By asking households about theirperception of the adequacy of water at their drawing points, we can estimatethe volume of water in this scale using survey data.