From 2009 through 2015 the TBIWRD supported SWC and tree planting in 163 micro-watersheds covering some 860 km<sup>2</sup> . The main objective was to improve vegetative cover in order to reduce water and sediment runoff so as to contribute to the long-term economic well-being of farmers and increase their resilience to future climate change and severe weather. Although lack of data on the exact location and timing of activities supported by the project imposes limitation in identifying effects of specific measures and the extent to which they vary with watershed features, we have aggregated annual micro-watershed data on areas of land, both cultivated and degraded, where SWC activities occurred and areas were planted with trees. Multispectral Landsat 7 imagery can then be used to create time series of vegetative conditions on the ground before and after the project by computing indices that are routinely used in the remote sensing literature. We use the Normalized Difference Vegetation Index (NDVI) and the Soil Adjusted Vegetation Index (SAVI) to measure vegetation cover and photosynthetic activity and the Land Surface Water Index (LSWI) as a measure of plant and soil water content. To assess the impact of TBIWRD we compute seasonal averages for each index for 30x30 m pixels for the 5-year period before TBIWRD started and the 7 years of its activity. Defining a control area by drawing a 5-km buffer around treated areas allows us to use a difference-in-differences (DID) specification with pixel-level fixed effects for identification.

Our results support that project activities stimulated improvements in soil water content and vegetation cover. Estimated impacts are largest for changes in soil water-holding capacity (approximated by the LSWI) and estimated elasticities are highest for SWC on degraded land, followed by SWC on cultivated land and tree planting. For all indices considered here, the estimated impact of interventions completed two or more years ago is two to three times larger than the effect of those implemented during the last year, consistent with the notion that project benefits are sustained and accumulate over time. Estimated impacts vary by season and index in plausible ways: SWC activities are estimated to increase soil water content in rainy and dry seasons, which allows more vegetative cover to endure through the pre-rainy season, but planting trees results in an increase in vegetative cover that is spread equally across seasons.

Unfortunately, there are few comparable studies that could be used to interpret the size of the estimated coefficient to assess if, beyond statistical significance, estimated impacts are meaningful economically. To partly address this, we complement the study of indices based on satellite imagery with analysis of groundbased measurements of water flows and sediment loads directly related to TBIWRD project objectives. Data on daily volumes of water flow and the amount of sediment that were collected during the project at hydrological stations in a subset of treated micro-watersheds make it possible to independently cross-check the imagery-based results. While identification is weaker and the econometric approach less rigorous than for the imagery-based indices, we find a highly significant association between project-supported SWC activities and a meaningful reduction in sediment.

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