We are working on a large scale Watershed Development in Maharashtra, India. We want to evaluate the outcomes of our work after 1 year. I was wondering what should be primary outcome variable. Sample size will depend on that.
The answer is probably going to depend on the intent. There may be a variety of desired outcomes ranging from increased production of goods and services, flood control, etc. Perhaps an outcome less often asked would be is the development consistent with the streams to be stable, able to move water and sediment without excessive erosion of stream banks, channel aggradation or degradation. Are changes consistent with water quality and aquatic organisms? Were BMPs identified and applied to conserve riparian values? Was development and associated practices consistent with the long term needs of the land, people and water resources? But the evaluation of outcome and meaning to others, may depend on perspective. If your perspective is farmer, land owner, tax payer, fisherman, boater, urban or rural, rich or poor, flood zone dweller, water user, as well as politician, the answer may vary. Perhaps the greatest outcome is the decision is in balance with the needs and values of the community affected.
It all depends on the objective of the development work carried out. However, I feel that the improvement of quantity and quality of water coming out of the watershed is one of the most important outcomes. If we can improve these two, that means the watershed is in balanced and healthy condition and is capable of supporting the watershed functions.
There are two kinds of impact assessment. One is tangabile and another is non tangible benefits out of any watershed development programme. The following major parameteres/indicators should be evaluated.
1. Groundwater and surface water resource evaluation.
2. Vegetation index and soil moisture enrichment.
3. Crop yield and rate of sedimentation in watershed.
Did you complete an inventory of the fundamental assets of the principal aquatic, fauna and flora components of the watershed? If not, how do intend to measure impact of whatever tasks you intend to undertake in the watershed? If you did complete such an assessment, what are your intended target accomplishments. Was it “clean water?” Was it to improve wildlife habitat? It is helpful to understand your fundamental targets in order to provide a meaningful response to your question.
High water quality harvested during annul period is the most important outcome of a watershed. Large scale watershed is accompanied with some hydrologic complications during assessment of harvesting water. More details about the considered watershed may enable us provide more specific answers.