Impacts of Postdam Land Use/Land Cover Changes on Modification of Extreme Precipitation in Contrasting Hydroclimate and Terrain Features

2014 ◽  
Vol 15 (2) ◽  
pp. 777-800 ◽  
Author(s):  
Abel T. Woldemichael ◽  
Faisal Hossain ◽  
Roger Pielke
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Extreme Precipitation ◽  
Windward Side ◽  
Leeward Side ◽  
Land Use Land Cover ◽  
Climate Feedbacks ◽  
River Watershed ◽  
Flat Terrain ◽  
Terrain Features

Abstract Understanding the impact of postdam climate feedbacks, resulting from land use/land cover (LULC) variability, on modification of extreme precipitation (EP) remains a challenge for a twenty-first-century approach to dam design and operation. In this study, the Regional Atmospheric Modeling System (RAMS, version 6.0) was used, involving a number of predefined LULC scenarios to address the important question regarding dams and their impoundments: How sensitive are the hydroclimatology and terrain features of a region in modulating the postdam response of climate feedbacks to EP? The study region covered the Owyhee Dam/Reservoir on the Owyhee River watershed (ORW), located in eastern Oregon. A systematic perturbation of the relative humidity in the initial and boundary condition of the model was carried out to simulate EP. Among the different LULC scenarios used in the simulation over the ORW, irrigation expansion in the postdam era resulted in an increase in EP up to 6% in the 72-h precipitation total. The contribution of the reservoir on EP added 8% to the 72-h total when compared to the predam LULC conditions. To address the science question, a previously completed investigation on the Folsom Dam [American River watershed (ARW)] in California was compared with the ORW findings on the basis of contrasting differences in hydroclimatology and terrain features. The results indicate that the postdam LULC change scenarios impact EP of ORW (Owyhee Dam) much greater than the EP of the ARW (Folsom Dam) because of its semiarid climate and flat terrain. EP was less sensitive to LULC changes on the windward side of the mountainous terrain of ARW as compared to the leeward side of the flat terrain of ORW.

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

2014 ◽  
Vol 18 (9) ◽  
pp. 3711-3732 ◽  
Author(s):  
A. T. Woldemichael ◽  
F. Hossain ◽  
R. Pielke Sr.
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Energy Budget ◽  
Atmospheric Modeling ◽  
Dew Point ◽  
Precipitation Event ◽  
Land Use Land Cover ◽  
River Watershed ◽  
Precipitation Patterns ◽  
Lulc Changes

Abstract. This study adopted a differential land-use/land-cover (LULC) analysis to evaluate dam-triggered land–atmosphere interactions for a number of LULC scenarios. Two specific questions were addressed: (1) can dam-triggered 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 dam-triggered 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.

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

2014 ◽  
Vol 11 (5) ◽  
pp. 5037-5075 ◽  
Author(s):  
A. T. Woldemichael ◽  
F. Hossain ◽  
R. Pielke
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Energy Budget ◽  
Convective Available Potential Energy ◽  
Atmospheric Modeling ◽  
Precipitation Event ◽  
Land Use Land Cover ◽  
River Watershed ◽  
Precipitation Patterns ◽  
Lulc Changes

Abstract. This study adopted a differential land-use/land-cover (LULC) analysis to evaluate dam-triggered land–atmosphere interactions for a number of LULC scenarios. Two specific questions were addressed: (1) can dam-triggered LULC heterogeneities modify surface and energy budget which, in turn, change regional convergence and precipitation patterns? and (2) how extensive is the modification in surface moisture and energy budget altered by dam-triggered 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 in dewpoint (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 to 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.

scholarly journals Enset-Based Land Use Land Cover Change Detection and Its Impact on Soil Erosion in Meki River Watershed for Sustainability of Lake Ziway, Western Lake Ziway Sub-Basin, Central Rift Valley of Ethiopia

2020 ◽  
Author(s):  
Alemu Beyene Woldesenbet ◽  
Sebsebe Demisew Wudmatas ◽  
Mekuria Argaw Denboba ◽  
Azage Gebreyohannes Gebremariam
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Land Cover Change ◽  
Soil Loss ◽  
Land Use Land Cover ◽  
River Watershed ◽  
Land Use Systems ◽  
Management Interventions ◽  
Land Use System

Abstract Background Water erosion, upland degradation and deforestation are the key environmental problems in Meki river watershed where this study was conducted. This study assessed the land use land cover change (LULCC) over the last 30 years, examined the contribution of Enset-Based land use system (EBLUS) to manage soil erosion problem for sustainability of Lake Ziway and suggested appropriate management interventions for the watershed ERDAS imagine 2014, Geo-statistical interpolation and RUSLE model was devised for LULCC detection and analysis, for different spatial inputs and soil loss modeling respectively. Result Meki river watershed covers 2110.39056 km² of area which is dominantly covered by cultivated land use system (41.5%), Enset-Based land use system (EBLUS)(10.65%), Bush and Chat land use system (25.6%), Forest and plantations land use system (14.14%), built up (7.4%) and water bodies (0.75%). Severity class of High to severe range (18-125tha-1yr-1) recorded in the sub-watersheds irrespective of the land use systems and facing sever degradation problem that increase in soil loss in all land use systems from 1987 to 2017. The average soil loss of 30.5tha-1yr-1 and 31.905tha-1yr-1 recorded from Enset growing zones and non-Enset growing zones of the watershed respectively.Conclusion Enset-Based land use system (EBLUS) saves significant amount of soil despite the steepness of the slopes of the Enset growing zones of the watershed. Hence, expansion of EBLUS can contribute in sustaining Lake Ziway by reducing soil loss rate and sedimentation problem for ecological sustainability of the watershed. Therefore, separate land use policy and awareness creation are mandatory for such EBLUS expansion, integrated watershed management and conservation of the natural environment.

scholarly journals Enset-based land use land cover change detection and its impact on soil erosion in Meki river watershed, Western Lake Ziway Sub-Basin, Central Rift Valley of Ethiopia

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Alemu Beyene Woldesenbet ◽  
Sebsebe Demisew Wudmatas ◽  
Mekuria Argaw Denboba ◽  
Azage Gebreyohannes Gebremariam
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Land Cover Change ◽  
Soil Loss ◽  
Management Practices ◽  
Water Bodies ◽  
Land Use Land Cover ◽  
River Watershed ◽  
Management Interventions

Abstract Background Water erosion, upland degradation and deforestation are key environmental problems in the Meki river watershed. The study assessed the land use land cover change (LULCC) for 30 years and it examined the contribution of indigenous Enset-based land use system (EBLUS) to reduce soil erosion and prevent water bodies including Lake Ziway from sedimentation which was not considered in the former studies. GPS based data collected and satellite based LULC analysis using ERDAS Imagine 2014 performed to investigate existing farm management practices and land cover respectively. HEC-GEOHMS, Geo-statistical interpolation and RUSLE were applied to model watershed characteristics, spatial climate parameters and soil loss respectively. Result Meki river watershed (2110.4 km2 of area) is dominantly covered by cultivated LUS (41.5%), EBLUS (10.65%), Bush and Chat LUS (25.6%), Forest and plantations LUS (14.14%), built-up (7.4%) and water bodies (0.75%). Soil loss is increasing from 1987 to 2017 and a larger part of the watershed suffers a moderately severe to very severe risk (18 t ha−1 year−1 to > 80 t ha−1 year−1) in all sub-watersheds irrespective of the land use systems which shows the watershed is facing sever degradation problem. The mean soil loss of 30.5 t ha−1 year−13 and 31.905 t ha−1 year−1 are verified from Enset growing zones and non-Enset growing zones of the watershed respectively. Conclusion EBLUS saves significant amount of soil despite the steepness of the slopes of the Enset growing zones of the watershed. Hence, expansion of EBLUS can contribute in sustaining water bodies, including Lake Ziway by reducing soil loss rate and sedimentation problem for the ecological sustainability of the watershed. Therefore, separate land use policy and awareness creation are mandatory for such EBLUS expansion, sustainable watershed management interventions and conservation of the natural environment in the watershed based on its suitability and severity of erosion risk mapping.

scholarly journals Enset-Based land use land cover change detection and its impact on soil erosion in Meki river watershed, Western Lake Ziway Sub-Basin, Central Rift Valley of Ethiopia

2020 ◽  
Author(s):  
Alemu Beyene Woldesenbet ◽  
Sebsebe Demisew Wudmatas ◽  
Mekuria Argaw Denboba ◽  
Azage Gebreyohannes Gebremariam
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Land Cover Change ◽  
Soil Loss ◽  
Management Practices ◽  
Water Bodies ◽  
Land Use Land Cover ◽  
River Watershed ◽  
Management Interventions

Abstract Background Water erosion, upland degradation and deforestation are key environmental problems in the Meki river watershed. The study assessed the land use land cover change (LULCC) for 30 years and it examined the contribution of indigenous Enset-Based land use system (EBLUS) to reduce soil erosion and prevent water bodies including Lake Ziway from sedimentation which was not considered in the former studies. GPS based data collected and satellite based LULC analysis using ERDAS Imagine 2014 performed to investigate existing farm management practices and land cover respectively. HEC-GEOHMS, Geo-statistical interpolation and RUSLE were applied to model watershed characteristics, spatial climate parameters and soil loss respectively. Result Meki river watershed (2110.4sq.km of area) is dominantly covered by cultivated LUS (41.5%), EBLUS (10.65%), Bush and Chat LUS (25.6%), Forest and plantations LUS (14.14%), built-up (7.4%) and water bodies (0.75%). Soil loss is increasing from 1987 to 2017 and a larger part of the watershed suffers a moderately severe to very severe risk (18 t ha-1yr-1 to >80 t ha-1yr-1) in all sub-watersheds irrespective of the land use systems which shows the watershed is facing sever degradation problem. The mean soil loss of 30.5 t ha-1yr-1 and 31.905 t ha-1yr-1 are verified from Enset growing zones and non-Enset growing zones of the watershed respectively. Conclusion EBLUS saves significant amount of soil despite the steepness of the slopes of the Enset growing zones of the watershed. Hence, expansion of EBLUS can contribute in sustaining water bodies, including Lake Ziway by reducing soil loss rate and sedimentation problem for the ecological sustainability of the watershed. Therefore, separate land use policy and awareness creation are mandatory for such EBLUS expansion, sustainable watershed management interventions and conservation of the natural environment in the watershed based on its suitability and severity of erosion risk mapping.

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