Evaluation of surface properties and atmospheric disturbances caused by post-dam alterations of land use/land cover

Abstract

Abstract. This study adopted a differential land-use/landcover (LULC) analysis to evaluate dam-triggered landatmosphere interactions for a number of LULC scenarios. Two specific questions were addressed: (1) can damtriggered LULC heterogeneities modify surface and energy budget, which, in turn, change regional convergence and precipitation patterns? (2) How extensive is the modification in surface moisture and energy budget altered by damtriggered LULC changes occurring in different climate and terrain features? The Regional Atmospheric Modeling System (RAMS, version 6.0) was set up for two climatologically and topographically contrasting regions: the American River watershed (ARW), located in California, and the Owyhee River watershed (ORW), located in eastern Oregon. For the selected atmospheric river precipitation event of 29 December 1996 to 3 January 1997, simulations of three pre-defined LULC scenarios are performed. The definition of the scenarios are (1) the "control" scenario, representing the contemporary land use, (2) the "pre-dam" scenario, representing the natural landscape before the construction of the dams and (3) the "non-irrigation" scenario, representing the condition where previously irrigated landscape in the control is transformed to the nearby land-use type. Results indicated that the ARW energy and moisture fluxes were more extensively affected by dam-induced changes in LULC than the ORW. Both regions, however, displayed commonalities in the modification of land-atmosphere processes due to LULC changes, with the control-non-irrigation scenario creating more change than the control-pre-dam scenarios. These commonalities were: (1) the combination of a decrease in temperature (up to 0.15 • C) and an increase at dew point (up to 0.25 • C) was observed; (2) there was a larger fraction of energy partitioned to latent heat flux (up to 10 W m −2 ) that increased the amount of water vapor in the atmosphere and resulted in a larger convective available potential energy (CAPE); (3) low-level wind-flow variation was found to be responsible for pressure gradients that affected localized circulations, moisture advection and convergence. At some locations, an increase in wind speed up to 1.6 m s −1 maximum was observed; (4) there were also areas of well-developed vertical motions responsible for moisture transport from the surface to higher altitudes that enhanced precipitation patterns in the study regions.

The Social, Economic, and Ecological Drivers of Planning and Management of Urban River Parks

“…Other impacts of the dam on ecological processes include the trapping of sediments behind the dam, which can result in incision in the channel downstream, and reductions in flow downstream, with potentially severe ecological consequences (Wisheropp, 2018;Gabet and Miggins, 2020). Dams also influence the regional landscape through alterations in land use after the dam was built, which can influence microclimate and weather patterns (Woldemichael et al, 2012(Woldemichael et al, , 2014a. Finally, the impact of recreation on the ecological system is also a source of concern for the American River Parkway Foundation and the Green Space Management Department of the city of Munich and has also been partly investigated (Zingraff-Hamed et al, 2018b.…”

Hydrological response to land use land cover and climate variability, and simulation of sediment export and water yield in the catchment Kotri Sindh Pakistan using Soil and Water Assessment tool model

“…[2][3][4] The rapid emergence and widespread climate change, resulting from the rise of natural and human-induced factors in the 21st century, 5 led to influential changes in hydrological components and many watersheds. 6 However, alteration in land use land cover (LULC) affects the apportionment of water among diverse hydrological pathways, 7,8 which in turn, leads to change in water distribution, entering through the path of vegetation and soil, such as interception, runoff, infiltration, groundwater recharge, 9,10 soil moisture, soil moisture storage, percolation, lateral flow. 11,12 Hence, it affects runoff generation.…”