Impact of Climate Change on Soil Erosion in the Lam Phra Phloeng Watershed

Uba Sirikaew,Jatuwat Wattanasetpong,Virun Chulkaivalsucharit,Walter Chen,Pinit Tanachaichoksirikun,Uma Seeboonruang

doi:10.3390/w12123527

Uba Sirikaew, Jatuwat Wattanasetpong + Show 4 more

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https://doi.org/10.3390/w12123527

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Abstract

Soil erosion plays a vital role in reducing reservoir capacity. The Lam Phra Phloeng (LPP) dams were built for flood protection and irrigation. However, they have experienced reservoir sedimentation, and the capacity of the reservoir has decreased. The surrounding soil surface was easily eroded and transported by heavy rainfall and surface runoff to streams and eventually into the reservoir. Understanding this soil erosion and sedimentation is necessary for preventing further decline of reservoir capacity and water management. This research aims to estimate long-term average annual soil erosion and predict sediment yield in the reservoir due to climate change. The methodology is determined soil loss parameters and sediment yield using the Universal Soil Loss Equation (USLE) with the Sediment Delivery Ratio (SDR). The USLE and SDR methods differed from field data, with an average absolute error of 4.0%. The Global Climatic Model, Institute Pierre Simon Laplace-Climate Model version 5A (IPSL-CM5A-MR), with Representative Concentration Pathways (RCP) 2.6, 4.5, and 8.5, was downscaled and analyzed to forecast future rainfall in the watershed. The high intensity of rainfall contributed to higher soil erosion, in RCP 8.5. Interestingly, the high and very high-risk areas increased, but the moderate risk area declined, indicating that the moderate risk area should be a priority in land management. However, the heavy rainfall and high slope gradient led to a slight increase in the soil erosion in some areas because the land covers were evergreen and deciduous forest. The prediction of sediment yield was positively correlated with the intensity of rainfall in the central part of the watershed, because the rainfall and runoff led the sediment to the river and streams, indicating that the land cover should be managed to prevent capacity decline.

Highlights

Nowadays global disasters are being caused by human activity and climate change [1,2].One problem is soil erosion, affecting the ecosystem, public utility system, and agricultural productivity [3]
Under Representative Concentration Pathways (RCP) 2.6, very low risk areas of soil erosion increased (≈2% of area), and very high risk areas decreased in the near, mid, and far future, the positions of these high risk area are a priority for water management and for plans to protect the Lam Phra Phloeng (LPP) dam, since there is less rainfall in the center of the LPP and more in the evergreen forest area, and the average annual rainfall declined by about 4.8%, 4.8%, and 7.2%.Under RCP 4.5, the average annual rainfall change, vs the baseline, was about +1.8%, +6.4%, and +8.1%
Estimation of soil erosion in a watershed is necessary for water management and dam protection

Summary

Introduction

Nowadays global disasters are being caused by human activity and climate change [1,2]. One problem is soil erosion, affecting the ecosystem, public utility system, and agricultural productivity [3]. Several factors affect soil erosion, such as water, ice (glacier), snow, air (wind), plants, animals, and human action [4]. A soil erodes slowly over most areas, but it erodes significantly in areas with heavy rainfall, high slope, intensive agriculture, deforestation, and urban sprawl. Soil erosion causes sediments to advect to rivers or streams, which leads to dead storage. Sedimentation increases the load on dams and decreases the useful storage capacity of reservoirs. Soil loss in the watershed of the Shihmen

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