The role of check dams in retaining organic carbon and nutrients. A study case in the Sierra de Ávila mountain range (Central Spain) J. Mongil-Manso a,c, ⁎, V. Díaz-Gutiérrez a,c , J. Navarro-Hevia b,c , M. Espina a,c , L. San Segundo a,c a Hydrology and Conservation Research Group, Catholic University of Ávila, Ávila, Spain b Department of Agricultural and Forestry Engineering, University of Valladolid, Palencia, Spain c Forest, Water and Soil Research Group, Palencia, Spain HIGHLIGHTS • We estimated the sediment trapped by check dams using the most accurate method. • Our topographic method allowed to es- timate soil organic carbon in a reliable way. • We also showed the importance of check dams in carbon sequestration. • We showed the importance of check dams in retaining sediment and soil nu- trients. • Our method allows to estimate sedi- ment, carbon and nutrient in non- monitored basins. GRAPHICAL ABSTRACT abstract article info Article history: Received 5 September 2018 Received in revised form 5 December 2018 Accepted 6 December 2018 Available online 07 December 2018 Soil organic carbon plays an important role in the global carbon cycle, accounting for 70% of the Earth's carbon. However, soil erosion can have a major impact on the stocks of soil carbon and other soil nutrients, such as nitro- gen and phosphorous. Soil and water conservation techniques, such as the building of check dams, are usually employed to control sediment yields and the losses of other soil components. The aim of this research is thus to quantify the soil organic carbon (SOC), soil nitrogen (SN) and soil phosphorous (SP) retained by the check dams of a hydrologic and forest restoration project in the Sierra de Ávila mountain range (Ávila, Central Spain). Soil samples were taken from the sediment wedges of 30 check dams and from 30 native soils. Soil tex- ture, electric conductivity, pH, C, N and P were measured in all the soil samples. The volume of sediment retained by the check dams was calculated by the Sections Method, which is very accurate in estimating the real volume of the sediment wedges. The total sediment yield in the area was thus estimated at 6.40 Mg·ha -1 ·yr -1 and the mean SOC, SN and SP densities were respectively 13.76, 0.48 and 0.05 kg·m -2 . These findings thus are very re- liable and allow us to conclude that check dams constitute an important instrument for controlling losses of SOC, SN and SP, and preventing these substances from passing into watercourses downstream of the area. © 2018 Elsevier B.V. All rights reserved. Keywords: Check dams Nitrogen Phosphorus Sediment yield SOC Soil erosion 1. Introduction Soil erosion is one of the most important environmental problems worldwide. Globally, 1094·10 6 ha are affected by water erosion, 751·10 6 ha of which are seriously damaged (Lal, 2003). Erosion Science of the Total Environment 657 (2019) 1030–1040 ⁎ Corresponding author at: Hydrology and Conservation Research Group, Catholic University of Ávila, Ávila, Spain. E-mail address: jorge.mongil@ucavila.es (J. Mongil-Manso). https://doi.org/10.1016/j.scitotenv.2018.12.087 0048-9697/© 2018 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv