Modeling the distributed effects of forest thinning on the long-term water balance and streamflow extremes for a semi-arid basin in the southwestern US
To achieve water resource sustainability in the water-limited southwestern US, it is critical to understand the potential effects of proposed forest thinning on the hydrology of semi-arid basins, where disturbances to headwater catchments can cause significant changes in the local water balance comp...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-03-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/20/1241/2016/hess-20-1241-2016.pdf |
| Summary: | To achieve water resource sustainability
in the water-limited southwestern US, it is critical to understand the
potential effects of proposed forest thinning on the hydrology of semi-arid
basins, where disturbances to headwater catchments can cause significant
changes in the local water balance components and basinwise streamflows. In
Arizona, the Four Forest Restoration Initiative (4FRI) is being developed
with the goal of restoring 2.4 million acres of ponderosa pine along the
Mogollon Rim. Using the physically based, spatially distributed triangulated irregular network (TIN)-based Real-time Integrated Basin Simulator (tRIBS) model, we examine the potential impacts of the 4FRI on the hydrology of Tonto Creek, a basin in the Verde–Tonto–Salt (VTS) system, which provides much of the
water supply for the Phoenix metropolitan area. Long-term (20-year)
simulations indicate that forest removal can trigger significant shifts in
the spatiotemporal patterns of various hydrological components, causing
increases in net radiation, surface temperature, wind speed, soil
evaporation, groundwater recharge and runoff, at the expense of reductions
in interception and shading, transpiration, vadose zone moisture and snow
water equivalent, with south-facing slopes being more susceptible to enhanced
atmospheric losses. The net effect will likely be increases in mean and
maximum streamflow, particularly during El Niño events and the winter
months, and chiefly for those scenarios in which soil hydraulic conductivity
has been significantly reduced due to thinning operations. In this particular
climate, forest thinning can lead to net loss of surface water storage by
vegetation and snowpack, increasing the vulnerability of ecosystems and
populations to larger and more frequent hydrologic extreme conditions on
these semi-arid systems. |
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| ISSN: | 1027-5606 1607-7938 |