Hunting for hints of streamflow depletion in hydrographs
Abstract
Groundwater pumping has led to a reduction in streamflow worldwide that is projected to increase throughout the 21st century. Reductions in streamflow caused by groundwater pumping, known as 'streamflow depletion', can be considerably lagged from when pumping occurs. Further, impacts on streamflow can be obscured by other causes of streamflow variability and it is therefore difficult to quantify streamflow depletion using observational data alone. However, hydrologic signatures, which are metrics derived from hydrographs that can be related to specific hydrologic processes, offer a potential approach to linking streamflow depletion to observed hydrologic change. Here, our goal is to investigate what hydrologic signatures are most sensitive to streamflow depletion across a wide range of environmental conditions under low-, average-, and high-flow conditions. Using an analytical modeling approach applied to over 200 sites spanning the continental United States, we found that low-flow signatures such as the mean annual seven-day low-flow and number of no-flow periods were most responsive to streamflow depletion. Additionally, effects of streamflow depletion were greatest in the summer and fall, most common in dry years, and least common in wet years. For most hydrologic signatures that were substantially affected by streamflow depletion, impacts were evident within short timescales (< 10 years) from the onset of pumping, but some impacts remained hidden during average and wet conditions and were only evident in dry conditions. These findings indicate that streamflow depletion can exacerbate already-low flows during drought periods. This suggests that quantifying changes in hydrologic signatures may be a useful, low-cost approach for identifying and monitoring potential streamflow depletion impacts in settings with interacting groundwater and surface water resources, providing a pathway towards identifying and mitigating negative impacts on ecosystems and society.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.H31B..02Z