Impact of climate change and land use on watershed runoff involves multiattribute ecohydrologic interactions. This information is critical to development of comprehensive stormwater management policies. Watersheds in the continental United States have diverse temperatures and precipitation regimes and varying hydrogeomorphic features that influence runoff. This study investigates watershed-scale runoff using statistical modeling for stormwater policy optimization. Multivariate statistical modeling show that vegetative activity, annual evaporation, precipitation, temperature and soil moisture significantly influenced watershed runoff. Soil moisture has a strong influence on runoff with each percent increase causing five percent increase in runoff. Nonlinear modeling with quadratic and interaction effects shows a significant interaction between soil moisture and other climatic variables in influencing annual runoff patterns. Changes in climate affect ecohydrologic characters by altering available soil moisture, evaporation, precipitation patterns and runoff. Optimization of green infrastructure design can be a successful management tool for runoff with an understanding that changes to multiple attributes in ecohydrologic variables affects runoff. Multi-attribute based green infrastructure and incentive policies can result in comprehensive stormwater policies that incorporate climatic and ecohydrologic conditions of watershed systems.