Geomorphology and ecohydrology of water-limited ecosystems : a modeling approach

The role of vegetation in shaping landforms and how these landforms respond to disturbances are the subjects of this work. A numerical model is developed to help develop a mechanistic understanding of the hydrological, ecological and geomorphic interactions in water-limited ecosystems. The growth of vegetation suppresses increases in runoff, thus reducing erosion efficiency and increasing topographic slopes as rainfall increases in dry climates. Moving along a climatic gradient to wetter climates leads to the point where the effect of vegetation is overwhelmed by increasing runoff, thus erosion efficiency increases and slopes decrease. This transition in vegetation controls translates into a minimum in drainage density for a semi-arid climate. Erosion efficiency is also affected by down-slope increases in vegetation, fostered by subsurface flow, an effect that reduces channel concavity. Plant characteristics also play a role in erosion by changing the variability of the vegetative effects. Comparing regions with the same fractional vegetation cover, those with faster growing or deeper rooted plants have greater erosion efficiencies.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Civil and Environmental Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Collins, Daniel B. G. (Daniel Benjamin Gardiner), 1976-

Advisor dc:contributor.advisor

• Rafael L. Bras.

• Civil and Environmental Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/38559

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/38559