UNDERSTANDING THE HISTORY OF WATER ON MARS IS FUNDAMENTAL TO THE SEARCH FOR EVIDENCE OF LIFE ON THAT PLANET. IN ADDITION TO DOCUMENTING WHERE AND WHEN WATER WAS PRESENT ON MARS IT IS CRITICAL TO DETERMINE HOW LONG IT WAS PRESENT ON THE SURFACE. THIS IS IMPORTANT BECAUSE THE STABILITY OF HYDROLOGIC SYSTEMS ON MARS HAS IMPLICATIONS AS TO WHERE EVIDENCE OF LIFE MAY BE FOUND. CURRENT ESTIMATES FOR HOW LONG LAKES LASTED ON MARS RANGE FROM DAYS TO TENS OF THOUSANDS OF YEARS OR LONGER AND ARE COMMONLY BASED ON THE DIMENSIONS AND MORPHOLOGY OF INFLOWING CHANNELS AND DELTA DEPOSITS. AN INDEPENDENT MEASURE OF LAKE PERSISTENCE AT A PARTICULAR LEVEL IS THE DEGREE OF SHORELINE DEVELOPMENT WHICH IS A RESULT OF THE AMOUNT OF WAVE ENERGY EXPENDED AT THAT ELEVATION OVER THE TIME OF FORMATION. ON EARTH WELL DEVELOPED AND WELL PRESERVED SHORELINE COMPLEXES IN LAKE BASINS CAN FORM ON ANNUAL TO DECADAL TIME SCALES. WE HAVE ADAPTED PHYSICS-BASED MODELS TO SIMULATE WAVE FORMATION PROPAGATION SHOALING AND SEDIMENT TRANSPORT CAPABILITY FOR WAVES ON MARS. PRELIMINARY RESULTS SUGGEST THAT LARGE WAVES WOULD HAVE TRAVERSED ICE-FREE MARTIAN LAKES AND HAVE BEEN CAPABLE OF MOVING COBBLE TO BOULDER-SIZED SEDIMENT AND BY EXTENSION FORMED RECOGNIZABLE SHORELINE COMPLEXES. THE PAUCITY OF POSITIVELY IDENTIFIED LAKE SHORELINES ON MARS IS THEREFORE PUZZLING BUT MAY INDICATE THAT THE LAKES WERE PRESENT ONLY BRIEFLY. BASED ON OUR INITIAL SURVEYS OF DOZENS OF CRATER LAKE BASINS ON MARS THE BEST SHORELINE CANDIDATES APPEAR TO BE ON THE FRONTS OF STEPPED AND PROGRADING DELTAS WHERE THERE ARE OFTEN PROMINENT OR SUBTLE BENCHES BUT WE ARE LOOKING IN OTHER PLACES AS WELL. THE OVERALL GOAL OF THE PROPOSED RESEARCH WILL BE TO CONSTRAIN THE DURATIONS OVER WHICH LAKES EXISTED ON MARS BY UTILIZING A COMBINATION OF PHYSICS-BASED WAVE MODELING AND RESULTANT SEDIMENT TRANSPORT GEOMORPHIC ANALYSIS AND COMPARISON TO LAKE SHORELINES ON EARTH THAT FORMED ON ANNUAL TO DECADAL TIMESCALES. WE WILL USE HIGH RESOLUTION DIGITAL TERRAIN MODELS (DTMS) DERIVED FROM HIRISE IMAGERY TO TEST PUTATIVE MARTIAN SHORELINE FEATURES FOR HORIZONTALITY A KEY CHARACTERISTIC OF SHORELINES ON EARTH. WE WILL ALSO DOCUMENT THE MORPHOLOGY AND DURATIONS OF FORMATION OF A SERIES OF HISTORICAL SHORELINE FEATURES IN THE GREAT BASIN OF THE WESTERN US. MODELING THE WAVE ENERGY DELIVERED TO THE EARTH SHORELINES OVER THEIR PERIODS OF FORMATION WILL ALLOW US TO RELATE THE AMOUNT OF WAVE ENERGY TO THE SHORELINE FORMATION PROCESS WHICH IN TURN CAN BE SCALED TO MARTIAN SHORELINES TO HELP ESTIMATE THEIR PERIODS OF FORMATION.