Nima Ehsani

Water Scientist

Investigating the qualitative and quantitative implications

     of climate change and anthropogenic disturbances

                     for the terrestrial water cycle

Reservoir Operations Under Climate Change: Storage Capacity Options to Mitigate Risk


  • The necessity and importance of dams in providing water security will increase
  • Effects of dams on downstream flows will be amplified
  • Effectiveness of existing dams in creating drought/flood resiliency will be limited
  • Increasing the size and number of dams may be necessary in the future



Observed changes in precipitation patterns, rising surface temperature, increases in frequency and intensity of floods and droughts, widespread melting of ice, and reduced snow cover are some of the documented hydrologic changes associated with global climate change. Climate change is therefore expected to affect the water supply-demand balance in the Northeast United States and challenge existing water management strategies. The hydrological implications of future climate will affect the design capacity and operating characteristics of dams. The vulnerability of water resources systems to floods and droughts will increase, and the trade-offs between reservoir releases to maintain flood control storage, drought resilience, ecological flow, human water demand, and energy production should be reconsidered. We used a Neural Networks based General Reservoir Operation Scheme to estimate the implications of climate change for dams on a regional scale. This dynamic daily reservoir module automatically adapts to changes in climate and re-adjusts the operation of dams based on water storage level, timing, and magnitude of incoming flows. Our findings suggest that the importance of dams in providing water security in the region will increase. We create an indicator of the Effective Degree of Regulation (EDR) by dams on water resources and show that it is expected to increase, particularly during drier months of year, simply as a consequence of projected climate change. The results also indicate that increasing the size and number of dams, in addition to modifying their operations, may become necessary to offset the vulnerabilities of water resources systems to future climate uncertainties. This is the case even without considering the likely increase in future water demand, especially in the most densely populated regions of the Northeast.


Watershed-Scale Assessment Of Innovative Drainage Practices
Preventing nutrient loss from Indiana farms by pairing cover crops and the two-stage ditch at a watershed-scale