This proposal seeks funds to enhance and expand a satellite-based, near-real time, reservoir and lake water-level monitoring system. This system is on-line, operational, existing within the US Department of Agriculture (USDA) decision support system (DSS) through the cooperative USDA/NASA Global Agricultural Monitoring (GLAM) program. Current lake level products stem from the NASA/CNES TOPEX/Poseidon (archival 1992-2002), NASA/CNES Jason-1 (post 2002 and near real time) and the US Naval Research Lab's GFO (post 2000) missions. The primary user is the Office of Global Analysis (OGA) within the USDA Foreign Agricultural Service (FAS). The FAS utilize the products for irrigation potential considerations and as general indicators of drought and high-water (flood) conditions. The monitoring system has relevance to water resources management and agriculture efficiency applications at both the national and international level. New objectives are: 1) To improve the quality and quantity of the current Jason-1 and GFO products. 2) To extend the 15year observations with near real time products derived from the follow-on NASA/CNES Jason-2 mission (launch, 2008). 3) To increase, by at least a factor of 5, the number of targets in the current system via the inclusion of ESA ERS-1, ERS-2 (1994-2002) and ENVISAT (near-real time) data. This greatly enhances the DSS, in particular by the inclusion of a large number of smaller reservoirs (100-300km2), and additionally provides a means to validate the current NASA/NRL products in regions where ground-based gauge data cannot be acquired. 4) With in-kind USDA support, continue the operational system with both NASA/CNES Jason-2 and ESA ENVISAT near real time products. 5) To provide an updated systems engineering report, which would include both an evaluation study and the results of the verification and validation exercises. The system will be benchmarked, stressing the overall value of the enhanced and expanded products to the USDA/FAS. An outline of the technical issues will be given and the original system requirements will be re-examined. This proposal utilizes and enhances NASA Earth Science products in a USDA decision support tool that primarily supports agricultural efficiency. The proposed program will continue the collaborative effort between the USDA, ESSIC/University of Maryland, NASA/GSFC Hydrological Sciences Branch and SGT Inc.