RIVERS ARE THE DOMINANT GEOLOGIC FORCES ACTING ON MUCH OF EARTH'S LAND SURFACE AND PLAY AN IMPORTANT ROLE IN MANY EARTH SYSTEMS. WHILE WE CAN LEARN MUCH ABOUT THEIR DYNAMICS FROM MODERN SYSTEMS THIS APPROACH IS LIMITED IN SCOPE TO PROCESSES OBSERVABLE ON HUMAN TIMESCALES. IN THE GEOLOGIC RECORD WE CAN SEE EVIDENCE FOR LARGE CHANGES IN TERRESTRIAL DRAINAGE DUE TO TECTONIC AND OTHER FORCINGS BUT THESE RECORDS DO NOT PRESERVE THE UPLAND LANDSCAPES WHERE SUCH CHANGES OCCURRED. I AIM TO BRIDGE THE GAP BETWEEN THE DETAILED BUT LIMITED UNDERSTANDING WE HAVE GAINED FROM THE MODERN WORLD AND THE LONGER-TERM EVIDENCE FOR CHANGE TO REVEAL THE PROCESSES BY WHICH FUNDAMENTAL CHANGES TO SURFACE DRAINAGE OCCUR OVER GEOLOGIC TIMESCALES AND THE TECTONIC AND CLIMATIC CONTROLS ON LANDSCAPE EVOLUTION. MY RESEARCH APPROACH IS TWO-FOLD. THE FIRST COMPONENT IS OBSERVATIONAL: I WILL USE THE DIVERSITY OF LANDSCAPES PRESENT ON THE MODERN EARTH TO SEEK PATTERNS IN DRAINAGE STABILITY OR INSTABILITY COMBINED WITH TERRAIN ANALYSIS AND CLIMATE DATA. I WILL ALSO INTERROGATE THE GEOLOGIC RECORD FOR LONGER-TERM EVIDENCE OF CHANGE TO SURFACE DRAINAGE AND MAKE USE OF SEVERAL REGIONAL CASE STUDIES OF DIFFERENT TECTONIC SETTINGS AS ANALOGUES TO OTHER EVENTS IN THE PAST. THE SECOND COMPONENT OF MY RESEARCH IS THE DEVELOPMENT OF A CONTINENTSCALE LANDSCAPE EVOLUTION MODEL WITH COUPLED SURFACE PROCESSES TECTONICS AND CLIMATE WHICH I WILL USE TO EXTEND THE RESULTS OF MY OBSERVATIONS TO SCENARIOS WE CANNOT DIRECTLY OBSERVE. I WILL CONDUCT A SUITE OF NUMERICAL EXPERIMENTS THAT SPAN THE RANGE OF PHYSICALLY REALISTIC SCENARIOS INCLUDING VARIATIONS IN CLIMATE TECTONIC ACTIVITY AND ROCK PROPERTIES. THESE SIMULATIONS WILL ALLOW ME TO CONNECT THE OUR MODERN PROCESS UNDERSTANDING OF RIVER DYNAMICS TO LONG-TERM GEOLOGIC CHANGE AND REVEAL MECHANISMS OF LANDSCAPE RESPONSE TO CHANGES IN TECTONIC AND CLIMATIC FORCINGS. BY INVESTIGATING THE MECHANISMS AND DRIVERS OF MAJOR CHANGES TO EARTH'S SURFACE AND BRINGING TOGETHER TECTONICS CLIMATE AND SURFACE PROCESSES I WILL DIRECTLY ADVANCE NASA'S OBJECTIVE TO ADVANCE KNOWLEDGE OF THE EARTH AS A SYSTEM. IN PARTICULAR MY RESEARCH ADDRESSES TWO OF NASA'S KEY QUESTIONS: TO DETERMINE HOW THE EARTH SYSTEM IS CHANGING AND WHAT CAUSES THESE CHANGES. RIVER NETWORKS ARE INTEGRALLY LINKED WITH MANY OTHER GEOLOGIC SYSTEMS AND ARE IMPORTANT NATURAL RESOURCES TO HUMAN SOCIETY. AN IMPROVED UNDERSTANDING OF THEIR CHANGES THROUGH TIME AND OF THEIR RELATIVE STABILITY WILL INFORM OTHER DISCIPLINES OF EARTH SCIENCE AND FACILITATE MORE EFFECTIVE USE OF THESE CRITICAL NATURAL RESOURCES.