SDR Model: riparian forest effect?

Dear InVEST users and developers,

I am using the SDR model to predict  sedimentation in a Brazillian watershed and to estimate the sediment avoided by a riparian forest in a reservoir inside this watershed. However, it seems the results underestimate the benefit of trapping sediments by a riparian forest, considering it as a regular forest elsewhere.

I suppose that a simple change in the riparian area CP parameter will not be enough as much of the acutal effect of the riparian is related to trap the sediment generated eleswhere.

I would like to know if is there a way to more accurately model the influence of a riparian forest. 

Thanks in advance!

Comments

  • RafaelRafael Member, NatCap Staff
    edited January 24
    Dear Luca



    Thank you for your question.



    As you point out, the benefit of planting a riparian forest will be first that it reduces
    local erosion where it is planted, i.e., close to the stream/reservoir
    banks, and second, that it t"raps" sediment that is eroded more upslope on its way to the stream.




    The trapping of sediment from upslope is covered via the connectivity
    factor (please see
    the documentation): You will see that the
    connectivity factor between any cell and the drainage network [see equation 6 and 7] is a
    function of the land use coefficient Ci of all downslope cells [via equation 5]. Hence,
    if a downslope cell is a fluvial buffer with a low value of Ci, it will reduce the sediment delivery
    from all upstream cells to the drainage network.




    If you have the feeling that the reduction of sediment delivery due to the fluvial buffer is too low according to measured data or your
    experience, you might try to create a new land use class for the
    Riparian Forrest. And assign that land use class a lower Ci than a normal forrest. However,
    that should be done considering relevant literature and if that is an appropriate
    assumption in your case. Some references for Ci(Forest) range from 
    0.0001–0.003, Table 2, to 0.001, Table 1. 

    Best Regards

    Rafael

    [For the NatCap hydrology team]
    Post edited by Rafael on
  • Rafael,

    Do you have the title of the paper for this link:


    It looks like when you click on it, it requires a login.
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