FUTURE HYDROLOGICAL FAILURE PROBABILITY OF DAMS IN NEW ENGLAND UNDER LAND USE AND CLIMATE CHANGE

Floods lead to the overtopping of dams which is the main cause of dam failures and can result in significant loss of lives and property. This study investigates how the hydrological failure probability of dams in New England may change with future changes in climate and land use. Non-stationarity of future precipitation caused by the anthropogenic climate change and altered watershed concentration times caused by anthropogenic alterations such as urbanization, industrialization or deforestation can impact the mechanisms of runoff production and transfer. This can potentially change the frequency, magnitude, or duration of floods. Therefore, due to different flood patterns and consequently different hydrological failure probability, dams in New England likely have very different future risk levels. As hydrological failure probability indicators, the magnitude and frequency, and duration of floods exceeding a threshold are used to determine the variability of hydrological failure probability. Aside from the historical measured and gridded climate and land use data, this study uses one high temporal- and spatial-resolution, dynamically downscaled climate change projection and 29 statistically downscaled climate change projections as well as four land use projections from “The New England Landscape Futures Project”. Results show that basin response in New England during high-flow events has not significantly changed during recent decades in spite of recent changes in climate and runoff generation mechanisms. Also, dammed basins with higher storage capacity are found to have a decrease in basin response and flood peaks while there is not enough evidence the significance of urban development on high-flow events in New England. It is likely that dams in New England experience higher levels of hydrological failure probability. This is because compared to historical data, future floods are likely to increase in magnitude and frequency, but they are not likely to last longer. Also, the results show more accentuated increase in the frequency compared to the magnitude of future floods. This study will help dam owners and state regulators plan for more resilient dam operations and more rigorous dam maintenance and account for the future risk associated with the approximately 15,000 dams in New England