The Iraqi Government is seriously considering the construction of a dam on the Euphrates River near the town of Haditha to better control water for irrigation on the Mesopotamian Plain, to generate hydropower and to alleviate flooding. The objective of the present study was to estimate the magnitude of possible losses from the reservoir due to seepage and evaporation. To estimate the water balance for the reservoir, all components must be estimated. Inflow was estimated based on the historical flow regime of the river but adjusted for the water requirements upstream in Syria and Turkey. Evaporation from the reservoir was estimated from pan evaporation data. Seepage losses were estimated by the Green and Ampt approach for infiltration. Complexity of the reservoir bed soil and limited data allowed only rough estimates of the water balance components. Annual expected evaporation losses from the reservoir was estimated to be 1.47 km³. The estimated seepage from the reservoir averages 0.47 km³/year for 11.5 years. Therefore, about 14% of inflow to the reservoir will be lost through seepage and evaporation for the first decade of operation. Further hydrological and geological studies are required before the feasibility of the project can be accurately assessed.

The Satpura region of Central India is characterized by hilly mountainous terrain and plateau country. The recent drilling of over 500 tube wells in the study area by the Evangelical Lutheran Church (E.L.C.) Water Development Project provided the data base for this study. Geologically, the area is underlain by crystalline rocks, basalts, and sandstones. Ground water flow systems are of the local and intermediate type. Well data such as yield, depth, depth of overburden, and aquifer depth were analyzed statistically according to rock type and topography. Wells drilled in valleys and flat uplands were the most productive and average well yields in crystalline rocks (23.9 gpm) were greater than In basalts (17.3 gpm) and sandstones (9.7 gpm). Linear and non-linear relationships among well parameters were analyzed to determine factors affecting well yields. Topographic location and fracturing were considered to be the predominant factors affecting well yields in the crystalline rocks. Well yield and specific capacity results were compared to results from areas of similar geology. Both step-drawdown and constant rate pumping tests were conducted on production wells. Step-test results indicated that well losses are significant in a number of wells tested and appear to be related to non-Darcian flow in the aquifer adjacent to the well. Constant rate pumping test results were analyzed by the Jacob-Cooper approximation to the Theis equation, and recovery data were analyzed by the residual drawdown method. Transmissivities in all three rock types ranged over two orders of magnitude, from 10² to 10⁴

The effect of altitude on individual storm precipitation in some of the San Dimas experimental watersheds is investigated. It is found that there is a well-defined increase of storm precipitation with altitude for storms greater than one inch. This increase is a linear function of storm depth. Using 41 storms of different magnitudes, a precipitation-altitude relationship is derived for a small area in the San Dimas Experimental Forest. The regionalization of this relationship and its transferability are tested by analyzing differences (errors) between computed and observed storm precipitation values in each case. In testing the regionalization of the precipitation-altitude relationship by computing mean areal storm precipitation over a larger area the standard error of estimate is around 11 percent. In transfering the same relationship the results are not as good and give a standard error of 16 percent. For individual points, however, the error is much higher. A rainfall-runoff model is used as a tool for evaluating the effect of precipitation errors, on simulated streamflow, in a watershed of 4.5 square miles. For annual flows, errors range between 3.4 and 12. 8 percent while errors in simulated monthly flows are as high as 22 percent. It is also evident that there is a strong dependence of the error magnitude on the state (wet, dry, etc.) of the preceding year or months, whichever is applicable. An error propagation is observed as a result of consistently over-estimating the precipitation input to the model. This evaluation is more of a qualitative nature and the values of error given should he viewed in this sense.