The Effect of Erosion Control Practices on the Vulnerability of Soil Degradation in Oued EL Malleh Catchment using the USLE Model Integrated into GIS, Morocco

Abstract

Water erosion is a major problem in semi-arid region where decreases the dam reservoir design capacity, agricultural yield productivity, and increases other environmental impacts. This phenomenon is widely predominant in Morocco, particularly in the Oued El Malleh watershed in the Casablanca Settat region. Most soil erosion happens gradually which makes it challenging to notice. Hence, the monitoring of soil degradation under a modelling-based, such as Geographic Information System (GIS) can help the decision-makers to quantify the eroded soil and choose the best mitigation measures. Many erosion control practices have been implemented in The Oued El Malleh watershed in 2008, which covers a surface area of 3127 km2. Even though, the soil erosion still dramatic in the region. To date, no one has attempted to work on the impact of the soil conservation factor at the level of the Oued El Malleh watershed, as well as monitoring the sustainability and effectiveness of the water erosion control practices already implemented. Therefore, periodic monitoring and evaluating soil degradation is imposed. To achieve this purpose, we used the Universal Soil Loss Equation (USLE) to spatially assess water erosion in the study area, to find out the most vulnerable area to erosion, to notice the efficiency of the actual erosion control practices and elaborate on new mitigation measures. The results of this study have been shown that the rate of soil loss in the Oued El Malleh, including the actual control erosion interventions, varies from 0 to 90 t. ha-1.year-1; with an average erosion rate of 0.65 t. ha-1.year-1. The study area characterized by a moderate to severe slopes, in some area, the Length and Steepness Factor LS exceeds 90 %. For this reason, we have been elaborated new soil loss map, including soil conservation measures according to the slope. The soil loss rate; following this approach; varies from 0 to 64 t.ha-1.year-1. Furthermore, the followed approach could be valuable for assessing the soil loss in similar area.
 HIGHLIGHTS
 
 Casablanca-Settat agricultural lands become progressively infertile and depleted soils
 Soil degradation by water erosion is a tidal problem in the Oued El Malleh watershed
 Soil loss was estimated at a watershed level using the USLE model and ArcGIS tool
 The soil loss rate is estimated to be 0.65 t. ha-1.year-1, and the average sedimentary yield is found at 8.27 t. ha-1.year-1
 Sustainable land management can limit soil degradation
 
 GRAPHICAL ABSTRACT

Predicting Daily Suspended Sediment Load Using Machine Learning and NARX Hydro-Climatic Inputs in Semi-Arid Environment

“…Meanwhile, the evaluation of the suspended sediment load (SSL) at basin scales could be valuable in classifying basin vulnerabilities to the soil erosion and, therefore, in prioritizing mitigation measures. The models of USLE and its derived versions are commonly applied approaches in Northern African countries to evaluate the soil erosion, including Morocco [27]. Recently, in our study [28], the comparison of two years of the sediment measurement with MUSLEbased simulation results demonstrated a low prediction accuracy, with a Nash-Sutcliffe efficiency index (NSE) lower than 0.5 [29].…”

Spatiotemporal ecosystem services: Response to structural changes (A case study in Lahijan, Iran)

“…This factor describes the role of conservative human measures in coping with water erosion in the soil. P values generally range from 0 to 1 depending on the measures and the slope (Mazigh et al, 2022). However, this study determined P Factor values for different LU classes according to the studies of Marques et al (2021) and Asadolahi et al (2018).…”

“…Vegetation protects against an aggressive climate by controlling the energy released by raindrops (Payet et al, 2012). This index arises from the four previous LU factors: vegetation, cover, elevation, and soil moisture, which are the most critical factors for estimating the impacts of nature and the percentage of vegetation on the amount of soil loss (Mazigh et al, 2022). The vegetation percentage can be evaluated from the NDVI index.…”

“…In this research, the R map was developed according to the studies of Panagos et al (2017). K i indicates the soil erodibility factor that represents the biophysical and chemical properties of the soil, indicating soil cohesion and resistance to erosion (Mazigh et al, 2022). This factor presents the ability of soil elimination by spraying and surface runoff and the effect of soil properties on erosion (Degife et al, 2021).…”

GIS based soil erosion assessment using the USLE model for efficient land management: A case study in an area with diverse pedo-geomorphological and bioclimatic characteristics

“…Since its establishment in the late 1960s, this empirical model has offered significant insights into the intricate mechanisms that regulate soil erosion. It has proven to be a pragmatic instrument for evaluating the hazards associated with soil loss and directing conservation endeavours in various geographical settings (Devatha et al, 2015;Girmay et al, 2020;Mazigh et al, 2022). Given the escalating complexities associated with alterations in land use, fluctuations in climatic patterns, and growing global environmental apprehensions, the USLE model has acquired heightened importance in the realm of current soil conservation and land management.…”