scholarly journals Effectiveness of Contour Farming and Filter Strips on Ecosystem Services

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1312 ◽  
Author(s):  
John Gathagu ◽  
Khaldoon Mourad ◽  
Joseph Sang
Keyword(s):  
Ecosystem Services ◽  
Sediment Yield ◽  
Water Conservation ◽  
Assessment Tool ◽  
Water Yield ◽  
Model Parameters ◽  
Subsequent Increase ◽  
Filter Strips ◽  
Filter Width ◽  
Annual Sediment

The failing ecosystem services in Thika-Chania catchment is manifested in the deterioration of water quality, sedimentation of reservoirs, and subsequent increase in water treatment costs due to high turbidity. The services can be restored by implementing relevant soil and water conservation practices to enhance flow regulation and control sediment yield. The impacts of contour farming and filter strips on water and sediment yield were evaluated using Soil Water and Assessment Tool (SWAT), Texas A&M University, USA. Sediment calibration and validation was achieved using data obtained from a bathymetric survey. Model parameters were adjusted to simulate the conservation impacts of contour farming and filter strips. Results indicated the average annual sediment yield as 22 t/ha at the outlet of the catchment and average annual surface runoff of 202 mm. The simulation results showed that filter strips of 5 m width would reduce the average annual sediment yield from the catchment by 54%. The efficacy of filter strips in reducing sediment yield was observed to increase with increasing filter width. Three-meter filter strips and contour farming reduced the average annual sediment yield at catchment outlet by 46% and 36%, respectively. It was concluded that the implementation of contour farming and filters strips reduced sediments by 63% from the base value. Water yield at the sub-basin level was only influenced by contour farming. The total water yield at the catchment outlet experienced no significant change.

CLIMATE- AND LAND USE-INDUCED RISKS TO WATERSHED SERVICES IN THE NYANDO RIVER BASIN, KENYA

2011 ◽  
Vol 47 (2) ◽  
pp. 339-356 ◽  
Author(s):  
MWANGI GATHENYA ◽  
HOSEA MWANGI ◽  
RICHARD COE ◽  
JOSEPH SANG
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Sediment Yield ◽  
Land Surface ◽  
Assessment Tool ◽  
Surface Condition ◽  
Water Yield ◽  
Minor Effect ◽  
Watershed Services

SUMMARYClimate change and land use change are two forces influencing the hydrology of watersheds and their ability to provide ecosystem services, such as clean and well-regulated streamflow and control of soil erosion and sediment yield. The Soil Water Assessment Tool, SWAT, a distributed, watershed-scale hydrological model was used with 18 scenarios of rainfall, temperature and infiltration capacity of land surface to investigate the spatial distribution of watershed services over the 3587 km2 Nyando basin in Western Kenya and how it is affected by these two forces. The total annual water yield varied over the 50 sub-basins from 35 to 600 mm while the annual sediment yield ranged from 0 to 104 tons ha−1. Temperature change had a relatively minor effect on streamflow and sediment yield compared to change in rainfall and land surface condition. Improvements in land surface condition that result in higher infiltration are an effective adaptation strategy to moderate the effects of climate change on supply of watershed services. Spatial heterogeneity in response to climate and land use change is large, and hence it is necessary to understand it if interventions to modify hydrology or adapt to climate change are to be effective.

scholarly journals Erosion index formulation with respect to reservoir life in the upper Citarum watershed

2018 ◽  
Vol 147 ◽  
pp. 03002
Author(s):  
Bakhtiar
Keyword(s):  
Sediment Yield ◽  
Assessment Tool ◽  
Average Value ◽  
Erosion Index ◽  
Dead Storage ◽  
The Mean ◽  
The Relationship ◽  
Water Assessment ◽  
Annual Sediment

This study aimed to formulate erosion index in the upper Citarum watershed with respect to the Saguling reservoir life. Soil and Water Assessment Tool model was incorporated to simulate hydrological processes in the catchment. From the calibration and validation results, the model is considerably of good performance. The simulated sediment inflow at Nanjung outlet was then extrapolated to determine the sediment inflow into the reservoir. The study revealed that the average value of sediment inflow into the reservoir is 29.24 tonnes/ha/year just below the tolerable erosion limit of 30 tonnes/ha/year assumed by Hammer (1981). It was also found that the relationship between sediment yield and sediment inflow is non linear. Erosion index is formulated as the ratio between the mean annual sediment yield generated in the watershed and the mean annual sediment yield that leads dead storage to be full in the designated life of the reservoir. Erosion index equals to 1.0 indicates that the dead storage will be full in the designated life of the reservoir. A classification of erosion index can be subsequently be made based on erosion index and reservoir life relationship.

scholarly journals Hydrologic modeling of a Himalayan mountain basin by using the SWAT mode

2017 ◽  
Author(s):  
Sharad K. Jain ◽  
Sanjay K. Jain ◽  
Neha Jain ◽  
Chong-Yu Xu
Keyword(s):  
Assessment Tool ◽  
Swat Model ◽  
Large Population ◽  
Water Yield ◽  
Model Parameters ◽  
Hydrologic Response ◽  
Water Balance Components ◽  
Daily Streamflow ◽  
Hydropower Potential ◽  
Himalayan Mountain

Abstract. A large population depends on runoff from Himalayan rivers which have high hydropower potential; floods in these rivers are also frequent. Current understanding of hydrologic response mechanism of these rivers and impact of climate change is inadequate due to limited studies. This paper presents results of modeling to understand the hydrologic response and compute the water balance components of a Himalayan river basin in India viz. Ganga up to Devprayag. Soil and Water Assessment Tool (SWAT) model was applied for simulation of the snow/rainfed catchment. SWAT was calibrated with daily streamflow data for 1992–98 and validated with data for 1999–2005. Manual calibration was carried out to determine model parameters and quantify uncertainty. Results indicate good simulation of streamflow; main contribution to water yield is from lateral and ground water flow. Water yield and ET for the catchments varies between 43–46 % and 57–58 % of precipitation, respectively. The contribution of snowmelt to lateral runoff for Ganga River ranged between 13–20 %. More attention is needed to strengthen spatial and temporal hydrometeorological database for the study basins for improved modeling.

scholarly journals Quantify the effects of watershed subdivision scale and spatial density of weather inputs on hydrological simulations in a Norwegian Arctic watershed

2021 ◽  
Author(s):  
Minh Tuan Bui ◽  
Jinmei Lu ◽  
Linmei Nie
Keyword(s):  
Assessment Tool ◽  
Potential Evapotranspiration ◽  
The Arctic ◽  
Water Yield ◽  
Spatial Density ◽  
Model Parameters ◽  
Snowmelt Runoff ◽  
Water Balance Components ◽  
Stream Length ◽  
Monthly Streamflow

Abstract The effects of watershed subdivisions on hydrological simulations have not been evaluated in the Arctic conditions yet. This study applied the Soil and Water Assessment Tool and the threshold drainage area (TDA) technique to evaluate the impacts of watershed subdivision on hydrological simulations at a 5,913-km2 Arctic watershed, Målselv. The watershed was discretized according to four TDA scheme scales including 200, 2,000, 5,000, and 10,000 ha. The impacts of different TDA schemes on hydrological simulations in water balance components, snowmelt runoff, and streamflow were investigated. The study revealed that the complexity of terrain and topographic attributes altered significantly in the coarse discretizations: (1) total stream length (−47.2 to −74.6%); (2) average stream slope (−68 to −83%); and (3) drainage density (−24.2 to −51.5%). The spatial density of weather grid integration reduced from −5 to −33.33% in the coarse schemes. The annual mean potential evapotranspiration, evapotranspiration, and lateral flow slightly decreased, while areal rainfall, surface runoff, and water yield slightly increased with the increases of TDAs. It was concluded that the fine TDAs produced finer and higher ranges of snowmelt runoff volume across the watershed. All TDAs had similar capacities to replicate the observed tendency of monthly mean streamflow hydrograph, except overestimated/underestimated peak flows. Spatial variation of streamflow was well analyzed in the fine schemes with high density of stream networks, while the coarse schemes simplified this. Watershed subdivisions affected model performances, in the way of decreasing the accuracy of monthly streamflow simulation, at 60% of investigated hydro-gauging stations (3/5 stations) and in the upstream. Furthermore, watershed subdivisions strongly affected the calibration process regarding the changes in sensitivity ranking of 18 calibrated model parameters and time it took to calibrate.

The Impacts of Land-Use Change Patterns on Soil Erosion in the Xixian Basin, China

2015 ◽  
Vol 737 ◽  
pp. 762-765 ◽  
Author(s):  
Yuan Yuan Han ◽  
Tao Cai
Keyword(s):  
Land Use ◽  
Time Series ◽  
Soil Erosion ◽  
Land Use Change ◽  
Sediment Yield ◽  
Water Conservation ◽  
Assessment Tool ◽  
Swat Model ◽  
Huaihe River ◽  
Soil And Water

To investigate the impacts of land-use patterns on the sediment yield characteristics in the upper Huaihe River, Xixian hydrological controlling station was selected as the case study site. Soil and Water Assessment Tool (SWAT) model was used to simulate land-use change effects on sediment yield by the use of three-phase (1980s, 1990s and 2000s) land-use maps, soil type map (1:200000) and 1987 to 2008 daily time series of rainfall from the upper Huaihe River basin. On the basis of the simulated time series of daily sediment concentration, land-use change effects on spatio-temporal change patterns of soil erosion modulus. The results revealed that under the same condition of soil texture and terrain slope the advantage for sediment yield was descended by woodland, paddy field and farmland. The outputs of the paper could provide references for soil and water conservation and river health protection in the upper stream of Huaihe River.

scholarly journals Future impacts of climate change on sediment influx rate in hydropower reservoir using SWAT

2021 ◽  
Vol 880 (1) ◽  
pp. 012024
Author(s):  
A Z Abdul Razad ◽  
S H Shamsuddini ◽  
A Setu ◽  
L Mohd Sidek
Keyword(s):  
Climate Change ◽  
Sediment Yield ◽  
Sediment Load ◽  
Assessment Tool ◽  
Annual Rainfall ◽  
Historical Period ◽  
Catchment Management ◽  
Influx Rate ◽  
Control Plan ◽  
Annual Sediment

Abstract Climate change causes more frequent and intense rainfall events, leading to severe erosion in the catchment and sediment transferred into rivers and reservoirs. This study focus on long term sediment load in major rivers in Cameron Highlands and prediction of annual sediment inflow into Ringlet Reservoir from 2000 to 2030. Soil Water Assessment Tool (SWAT) is used as the simulation tool, utilising future gridded rainfall 2017 to 2030 under CCSM and future land use 2030. Future annual rainfall is minimum at 1551 mm (in 2030) and maximum at 3150 mm (in 2029). The future projected annual sediment load into Ringlet Reservoir from 2017 to 2030 is averaged at 354,013 m3/year, ranging from 216,981 to 461,886 m3/year. Comparing between the historical period of 2000 to 2016 and future projection (2017–2030), annual sediment load shows an increase of 12 %. To combat the increase sediment yield, catchment management such as erosion control plan, drainage and runoff control must be developed to minimise sediment yield and subsequent effect of high sediment load transport via rivers and drainage network.

scholarly journals A collaborated framework to improve hydrologic ecosystem services management with sparse data in a semi-arid basin

2021 ◽  
Author(s):  
Yifan Wu ◽  
Yang Xu ◽  
Guodong Yin ◽  
Xuan Zhang ◽  
Chong Li ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Assessment Tool ◽  
Hydrological Cycle ◽  
Swat Model ◽  
Water Yield ◽  
Infiltration Capacity ◽  
Runoff Simulation ◽  
Invest Model ◽  
Integrated Valuation ◽  
Semi Arid

Abstract Applying various models to assess hydrologic ecosystem services (HESs) management has the potential to encourage efficient water resources allocation. However, can a single model designed on these principles be practical to carry out hydrologic ecosystem services management for all purposes? We address this question by fully discussing the advantages of the variable infiltration capacity (VIC) model, the soil and water assessment tool (SWAT), and the integrated valuation of ecosystem services and tradeoffs (InVEST) model. The analysis is carried both qualitatively and quantitatively at the Yixunhe River basin, China, with a semi-arid climate. After integrating the advantages of each model, a collaborated framework and model selection method have been proposed and validated for optimizing the HESs management at the data sparse scenario. Our study also reveals that the VIC and SWAT model presents the better runoff reproducing ability of the hydrological cycle. Though the InVEST model has less accuracy in runoff simulation, the interannual change rate is similar to the other two models. Furthermore, the InVEST model (1.08 billion m3) has larger simulation result than the SWAT model (0.86 billion m3) for the water yield, while both models have close results for sediment losses assessment.

scholarly journals Water and sediment yield estimation: A case study in Bawashaswar Watershed/ Iraqi Kurdistan Region

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Sarkawt G. Salar ◽  
◽  
Abdulhaq N. Mahmoud ◽  
Arsalan A. Othman ◽  
◽  
...  
Keyword(s):  
Sediment Yield ◽  
Assessment Tool ◽  
Ground Surface ◽  
Curve Number ◽  
High Water ◽  
Water Yield ◽  
Climatic Data ◽  
Wet Season ◽  
Runoff Water ◽  
Water And Sediment

Water flow in the seasonal streams forms a vital supplier of water resources, particularly in arid and semiarid areas due to its high water supply from the precipitation during the wet season. This research aims to estimate water and sediment yield in the Bawashaswar watershed (BW), which is far ~90 km from Kirkuk City and covers an area of 277 km2. The Bawashaswar Dam (BD) was constructed for multi-purposes, such as drinking, irrigation, livestock, and tourism at the outlet of the watershed north of Kifri town. The Soil Water Assessment Tool (SWAT) was integrated with several datasets, such as satellite images, Digital Elevation Model (DEM), land use, land cover, curve number (CN), daily climatic data of temperature, precipitation, and digital soil map to achieve the results. The estimated results include precipitation, evaporation transpiration, percolation, surface runoff, water yield, loss of transport, and sediment yield. The results showed that almost all the siltation (>0.5 ton/ha) comes from the western and northern parts of the BW due to the high topographic relief and the high channel discharge there. These results will support the future development plans and management of the watershed through mitigating and minimizing the size of the ground surface degradation problems all over the study area with increasing the lifespan of the BD.

scholarly journals Modeling runoff response to land-use changes using the SWAT model in the Mundaú watershed, Brazil

2020 ◽  
Vol 5 (2) ◽  
pp. 194-206
Author(s):  
Carolyne Wanessa Lins de Andrade Farias ◽  
Suzana Maria Gico Lima Montenegro ◽  
Abelardo Antônio de Assunção Montenegro ◽  
José Romualdo de Sousa Lima ◽  
Raghavan Srinivasan ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Sediment Yield ◽  
Surface Runoff ◽  
Assessment Tool ◽  
Swat Model ◽  
Land Use Changes ◽  
Water Yield ◽  
Grazing Land ◽  
Runoff And Sediment Yield

Land-use change has a significant influence on runoff process of any watershed, and the deepening of this theme is essential to assist decision making, within the scope of water resources management. The study was conducted for Mundaú River Basin (MRB) using the Soil and Water Assessment Tool (SWAT) model. The study aims to assess the issue of land-use change and its effect on evapotranspiration, surface runoff, and sediment yield. Input data like land use, topography, weather, and soil data features are required to undertake watershed simulation. Two scenarios of land use were analyzed over 30 years, which were: a regeneration scenario (referring to use in the year 1987) and another scene of degradation (relating to use in the year 2017). Land use maps for 1987 and 2017 were acquired from satellite images. Overall, during the last three decades, 76.4% of forest was lost in the MRB. The grazing land increased in 2017 at a few more than double the area that existed in 1987. Changes in land use, over the years, resulted in an increase of about 37% in the water yield of MRB. Changes have led to increased processes such as surface runoff and sediment yield and in the decrease of evapotranspiration. The spatial and temporal distribution of land use controls the water balance and sediment production in the MRB.

scholarly journals Evaluation of Ecosystem-Based Adaptation Measures for Sediment Yield in a Tropical Watershed in Thailand

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2767
Author(s):  
Mukand S. Babel ◽  
Miyuru B. Gunathilake ◽  
Manoj K. Jha
Keyword(s):  
Sediment Yield ◽  
Assessment Tool ◽  
Land Use Changes ◽  
Management Strategies ◽  
Watershed Model ◽  
Adaptation Measures ◽  
Severe Problem ◽  
Filter Strips ◽  
Tropical Watershed ◽  
Watershed Degradation

Ecosystem-based adaptation (EbA) can potentially mitigate watershed degradation problems. In this study, various EbA measures were evaluated using a bio-physical model called the Soil and Water Assessment Tool (SWAT), in a small, forested watershed named Hui Ta Poe, in the northeastern region of Thailand. The developed watershed model was first used to investigate the effect of various degraded watersheds due to land-use changes on the sediment yield in the study area. The most degraded watershed produced an annual average sediment yield of 13.5 tons/ha. This degraded watershed was then used to evaluate the effectiveness of various EbA measures such as reforestation, contouring, filter strips, and grassed waterways in reducing the sediment yield. Under all individual and combined EbA scenarios analyzed, there was a significant reduction in sediment yield; however, the maximum reduction of 88% was achieved with a combined scenario of reforestation, grassed waterways, and filter strips. Reforestation alone was found to be the second-best option, which could reduce the sediment yield by 84%. Contouring alone was the least effective, with a reduction in sediment yield of only 23%. This study demonstrates the usefulness of implementing EbA measures for sediment management strategies to address watershed degradation, which is a severe problem across the globe.

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