Article: Development of a morphometric connectivity model to mitigate sediment derived from storm-driven shallow landslides
Ecological engineering. 2022 July, v. 180
2022
Abstract: In silvopastoral environments, landslide erosion results in loss of productive soils and pasture. Sediment delivered to streams from landslides contributes to the degradation of freshwater and marine receiving environments by smothering benthic habitats ... ...
| Abstract | In silvopastoral environments, landslide erosion results in loss of productive soils and pasture. Sediment delivered to streams from landslides contributes to the degradation of freshwater and marine receiving environments by smothering benthic habitats and increasing turbidity, light attenuation, and sediment-bound contaminants. Biological mitigation is an important strategy in pastoral environments to combat landslide erosion and improve the health of downstream aquatic ecosystems. Using lasso logistic regression, we investigate determinants of sediment connectivity for a landslide-triggering storm event in 1977 in the Wairarapa, New Zealand. Furthermore, we develop the first morphometric connectivity model to predict the likelihood of sediment delivery to streams following landslide initiation. We explore a range of connectivity scenarios by defining a set of sinks and simulating varying rates of sediment generation during flood events of increasing magnitude. The likelihood of sediment delivery is greatly enhanced where landslide deposits coalesce. Besides scar size variables, overland flow distance and vertical distance to sink were the most important morphometric predictors of connectivity. When scar size variables were removed from the connectivity model, median AUROC was reduced from 0.88 to 0.75. By coupling landslide susceptibility and connectivity predictions in a modular form, we quantify the cost effectiveness of targeted versus non-targeted approaches to shallow landslide mitigation. Sediment delivery ratios range from 0.21 to 0.29, equating to an event sediment yield of 3548 t km⁻² to 9033 t km⁻². Targeted mitigation of landslide-derived sediment is approximately an order of magnitude more cost-effective than a non-targeted approach. Compared with a pasture-only baseline, a 34% reduction in sediment delivery can be achieved by increasing slope stability through spaced tree planting on 6.5% of the pastoral land. The maximum reduction achievable through comprehensive coverage of widely spaced planting is 56%. The landslide connectivity model provides an objective method to support management decisions relating to mitigation of landslide erosion and sediment delivery to streams. |
|---|---|
| Keywords | cost effectiveness ; freshwater ; landslides ; models ; morphometry ; overland flow ; pastoralism ; pastures ; regression analysis ; sediment yield ; sediments ; storms ; turbidity ; New Zealand |
| Language | English |
| Dates of publication | 2022-07 |
| Publishing place | Elsevier B.V. |
| Document type | Article |
| ZDB-ID | 1127407-4 |
| ISSN | 0925-8574 |
| ISSN | 0925-8574 |
| DOI | 10.1016/j.ecoleng.2022.106676 |
| Database | NAL-Catalogue (AGRICOLA) |
Full text online
More links
Kategorien
In stock of ZB MED Bonn / Germany
| Z 5865: Show issues |
Order via subito
This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.
Inter-library loan at ZB MED
Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.