Modeling Short-Term Landscape Modification and Sedimentary Budget Induced by Dam Removal: Insights from LEM Application

Dario Gioia,Marcello Schiattarella

doi:10.3390/app10217697

Dario Gioia, Marcello Schiattarella

Open Access

https://doi.org/10.3390/app10217697

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Abstract

Simulation scenarios of sediment flux variation and topographic changes due to dam removal have been investigated in a reservoir catchment of the axial zone of southern Italy through the application of a landscape evolution model (i.e.,: the Caesar–Lisflood landscape evolution models, LEM). LEM simulation highlights that the abrupt change in base level due to dam removal induces a significant increase in erosion ability of main channels and a strong incision of the reservoir infill. Analysis of the sediment dynamics resulting from the dam removal highlights a significant increase of the total eroded volumes in the post dam scenario of a factor higher than 4. Model results also predict a strong modification of the longitudinal profile of main channels, which promoted fluvial incision upstream and downstream of the former reservoir area. Such a geomorphic response is in agreement with previous analysis of the fluvial system short-term response induced by base-level lowering, thus demonstrating the reliability of LEM-based analysis for solving open problems in applied geomorphology such as perturbations and short-term landscape modification natural processes or human impact.

Highlights

Base-level variation has a significant impact on a geomorphological system with severe changes in channel incision rate, sediment flux, and spatial distribution of geomorphological processes [1,2,3].A fast transition from endorheic (i.e.: centripetal drainage or closed basin) to exorheic drainage is one of the most relevant cases of disequilibrium of a landscape, because it promotes a non-linear response of the fluvial systems and a complex spatial and temporal response of river incision and sediment flux
The post-dam removal catchment includes the steeper reach of the Ficocchia stream, which flows in a deep V-shape valley
Simulation scenarios of sediment flux variation and topographic changes due to dam removal have been investigated in a reservoir catchment of southern Italy through the application of a landscape evolution model (i.e.: the Caesar–Lisflood landscape evolution models (LEMs))

Summary

Introduction

Base-level variation has a significant impact on a geomorphological system with severe changes in channel incision rate, sediment flux, and spatial distribution of geomorphological processes [1,2,3].A fast transition from endorheic (i.e.: centripetal drainage or closed basin) to exorheic drainage is one of the most relevant cases of disequilibrium of a landscape, because it promotes a non-linear response of the fluvial systems and a complex spatial and temporal response of river incision and sediment flux (see for example [4]). Several works have investigated the long-term response of the drainage network to a transition from endorheic to exorheic conditions due to complex climateor tectonic-driven processes such as sediment overfilling, headward stream erosion, and threshold incision or fluvial capture [5,6,7,8]. This kind of analysis is largely based on morphotectonic studies and related qualitative reconstruction of past stages of landscape evolution [9,10,11].

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