Epsilon Archive for Student Projects

Abstract

Soil erosion and deposition are natural planetary phenomena. However, human activities such as conventional till agriculture and deforestation have increased the rate of erosion and subsequent soil degradation, consequently increasing the risks of for example global food insecurity. Also, eroded soil may be transported by waterways and deposit as sediment at locations where it can cause ecological or societal disturbances. As such, preventing erosion has become a prioritised policy globally in many sectors, and a strategic topic within the field of landscape architecture, planning and management.
Environmental models that estimate soil erosion and deposition by water are therefore of great importance. In landscape architecture, they can be used for spatial risk assessment to indicate erosion hotspots within a geographical area, and to recommend subsequent preventionary measures. Since the 20th century many attempts have been made to develop lumped or distributed models for such assessments, for example the LImberg Soil Erosion Model (LISEM). This study presents a prototype of, to my knowledge, the first soil erosion and deposition functionality added into a dynamic triangular flow algorithm (TFM-DYN). It uses a set of equations from LISEM implemented into TFM-DYN to estimate potential soil erosion, and sediment transport and deposition within a specific geographical area and time and uses data input regarding characteristics of the land and attributes of one or several rain events.
The results show that the added functionality generally meets the expected logic of erosion and deposition: soil is eroded based on the water’s transport capacity and, as sediment, transported and deposited according to the flow distribution of the dynamic triangular flow algorithm. However, the model needs additional calibration for practical use, and more experimentation to adjust deposition rate estimation, and so leaves room for improvement.