Al-Khoud dam, like many other dams in the world, face siltation problem. Siltation is the accumulation of fine soil particles on the soil surface. This layer of accumulated sediments reduces soil infiltration rates. The soil particles are carried with sediment rich flash floods after rainfall events. To combat this layer, the responsible authority in Oman removes the silt layer by mechanical scraping. However, this process is tedious, costly, and requires action after each flash flood. Moreover, the scrapping process does not solve the problem completely. That's because the saturated hydraulic conductivity of the dams' original coarse matrix is already reduced. This reduction is caused by clogging of large pores of the subsoils by fine sediments. Fine sediments migrate and translocate from the soil suspension into large pores in the soil matrix. In addition, because of its fine texture, the silt layer stores water. The stored water either evaporates or penetrates the deeper bottom soil layers of dam's reservoir. If the stored water evaporates, it's considered as a loss. Moreover, stored water remains ponded for longer time with the presence of silt layer. As a result, evaporation losses increase. Therefore, another solution is required to mitigate this problem and reduce water loss through evaporation and runoff. A suggested method is the cultivation of trees in the dam area. Trees' roots create cracks in the soil. These cracks provide preferential channels for water to seep through. In this study, Sidr trees are used as an infiltration inducing bioengineering in the Al-Khoud dam bed. Sidr tree was chosen because it's an indigenous (in Oman and other Gulf countries) tree that can survive under heat stress, water stress, and flooding. However, as a phreatophyte, Sidr trees in the dam area use groundwater as their main water source. Therefore, the quantification of the amount of water used by Sidr trees in the dam is required. This was done in the research using the sap flow meter. For an optimal cultivation of Sidr trees in the dam bed, the water balance in the dam should be evaluated. Based on the water balance in the dam reservoir, some scenarios are suggested for the optimal number of cultivated Sidr trees in the dam reservoir.