<p> Rainfall estimation from satellite observations has uncertainties and inconsistency at different locations and so four different satellite products were selected for validation in Saudi Arabia. The satellite products selected for this study are TRMM, PERSIANN, CMORPH, and GSMap-MVK which are compared with gauge observed rainfall data using conventional statistical methods at daily, 10-daily, and monthly time scale. The validation results show that all the products can predict rainfall in the study area reasonably well but overestimates rainfall in the regions. However, this bias is comparatively less in the semi-arid part of the country where most of the rain falls. Therefore, all the four satellite products were used in SWAT model to study the hydrologic response in a semi-arid watershed located in the western part of the country. Results show that simulation from TRMM rainfall estimates agrees better with that of gauge observations at daily time scale.</p>

<p> Communities worldwide face water supply challenges and often seek alternative sources of water. Recycled water is an alternative generated from wastewater to reduce non-potable uses of high quality water supplies for irrigation, industrial processes, power plant cooling, and toilet flushing. Researchers have recommended constructing the systems in new communities to reduce capital investment. The implementation of these systems is often financially difficult to justify within existing communities. Orange County Water District constructed a recycled water system, Green Acres Project (GAP), within existing communities in northern Orange County, California. The system delivers recycled water to four cities, reduces seawater intrusion, creates a benefit from a wastewater stream, and diversifies the region&rsquo;s water portfolio. As is common among recycled systems, the GAP has operated at a financial loss since its construction in the early 1990&rsquo;s. Through water sale revenues and a subsidy program, the District has been able to cover operational and maintenance costs but not capital. This study presents hydraulic and financial modeling to better understand the current GAP system and proposed changes. EPANET has been used to simulate five scenarios that include current operation, known future demand changes, breaking distribution loops, and increasing demand to balance finances. Analyzed financial scenarios include continued operation, breakeven finances, change in treatment technology, abandonment of system, and changing the local definition of recycled water. Recommendations to improve financial and operational efficiencies, challenges, and lessons learned from the GAP system are presented so other communities investigating implementation of recycled water programs may become better informed.</p>