InVEST Sediment Retention Model
Avoided dredging costs and water quality regulation
The InVEST Sediment Retention estimates the capacity of a land parcel to
retain sediment by using data on geomorphology, climate, vegetation and
management practices. These estimates are combined with data on
sediment removal costs, reservoir design, and a discount rate to value the
service of avoided sedimentation provided by natural systems. Limits of
the model include negligence of mass erosion, inadequate information
about sediment removal costs, and simplified LULC classifications.
Key Questions
Users can employ the InVEST model to answer the following questions:
Where are the nutrient pollution sources on this landscape?
Which parts of the landscape are most important for preventing
sediment pollution?
How much of the sediment pollutant is retained by natural
ecosystems? (I.e., How much pollution is prevented?)
What is the monetary value of this sediment retention service?
The model calculates the average annual soil loss from each parcel of
land, determines how much of that soil may arrive at a particular point of
interest, estimates the ability of each parcel to retain sediment, and
assesses the cost of removing the accumulated sediment on an annual
basis. To identify a land parcel’s potential soil loss and sediment
transport, the InVEST model uses the Universal Soil Loss Equation
(USLE) at the pixel scale, which integrates information on LULC patterns
and soil properties, as well as a digital elevation model (DEM), rainfall
and climate data. Pixel-scale calculations represent the heterogeneity of
key driving factors in water yield such as soil type, precipitation and
vegetation type. This model quantifies the total sediment retained at
the watershed or sub-watershed scale and the value of that sediment
to maintaining water quality or avoiding reservoir sedimentation. For
water quality, the model uses additional information on water quality
standards and treatment costs to value the ability of each sub-watershed
to reduce treatment costs. For reservoir maintenance, the model uses
data on reservoir location and the avoided cost of sediment removal to
value a sub-watershed’s capacity to prevent sedimentation.
Model Limitations
 Predicts erosion from sheet wash alone (no gully or bank erosion)
 All sediment erosion will reach the watershed outlet within a year
 Land cover has no upper limit on sediment retention
 Accuracy limited in mountainous areas
 Neglects the role of topography, soil, and climate
Sediment Retention
Model Features
Based on the Universal Soil
Loss Equation (USLE)
Enhanced by hydraulic
connectivity
Sediment retention valued
as an ecosystem service
User Inputs
Topography
Digital Elevation Model
(DEM), slope threshold
Erosivity
Based on intensity and kinetic
energy of rainfall
Watersheds
Catchments flowing into
points of interest
Land Use/Land Cover
(LULC)
Vegetation retention, land
practice and management
Economic Valuation
Sediment removal cost, water
treatment cost
Becky-Chaplin Kramer
bchaplin@stanford.edu
Lead Scientist
Natural Capital Project
naturalcapitalproject.org