1 / 9

The USLE/RUSLE Model:

Runoff as a factor in USLE/RUSLE Technology P.I.A. Kinnell, Institute for Applied Ecology, University of Canberra. The USLE/RUSLE Model: A = R K L S C P R and K have units, L = S = C = P = 1 on UNIT PLOT UNIT PLOT = 22.1 m long bare fallow on 9% slope

evelyn
Télécharger la présentation

The USLE/RUSLE Model:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra • The USLE/RUSLE Model: A = R K L S C P R and K have units, L = S = C = P = 1 on UNIT PLOTUNIT PLOT = 22.1 m long bare fallow on 9% slope cultivation up and down the slope • The model works mathematically in 2 steps A1 = R K UNIT PLOT is the primary physical model A = A1 L S C P • Factors are not independent in RUSLE and RUSLE2L = (slope length / 22.1 )m where m varies with rill to interill ratio which varies with soil properties and slope gradientC varies with climate through interaction between temporal variations in erosivity and crop growth 1/3 RUSLE2 Daily Erodibility Storm EI30, QR and Erodibility Predicted storm soil loss by RUSLE2 and USLE-M EGU2014

  2. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra • Soil loss depends on runoff but the R factor is based on event erosivity factor that does not include runoff as an independent variableConsequently, K, the soil loss per unit of R, for a soil with given physical properties will be greater for wet climates than for dry climates. • In RUSLE2Kj / Kn = 0.591 + 0.732 (Pj/Ps) – 0.324 (Tj/Ts) Tj > 30oF Kn = nomograph K, j = month, Ts = average summer temp, Ps = average summer monthly rain • Base climate = Columbia, Missouri 2/3 RUSLE2 Daily Erodibility Storm EI30, QR and Erodibility Predicted storm soil loss by RUSLE2 and USLE-M

  3. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra • Nomograph was developed from rainfall simulating experiments on 10.6 m long plots using a sequence of runs – dry (giving Kd), wet (giving Kw), very wet (giving Kvw) • K = (13 Kd + 4 Kw +3 Kvw) /20 (Dabney et al, 2004) Tillage treatmentKdKwKvw Conventional Till 0.33 0.58 0.76 No Till 0.37 0.84 0.89 K values in customary US unitsWeighting for climate in central USA. 3/4 RUSLE2 Daily Erodibility Storm EI30, QR and Erodibility Predicted storm soil loss by RUSLE2 and USLE-M

  4. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra • RUSLE2 can predict soil losses for a set of representative storms • USLE-Mincludes runoff as a factor in the event erosivity indexA1 = QR EI30 KUM QR = runoff ratio KUM = soil erodibility associated with QR EI30 index • A1 = QR EI30 KUM = EI30 [QR KUM ] • [QR KUM ] = a runoff dependent erodibility factor associated with EI30and can be compared with RUSLE2 Ks when applied to individual events 3/3 To 1 RUSLE2 Daily Erodibility Storm EI30, QR and Erodibility Predicted storm soil loss by RUSLE2 and USLE-M

  5. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra  Daily soil erodibility Daily temperature Frozenground in Winter Presque Isle, MEBethnay, MOMacon, GA Tampa, FL NorthSouth

  6. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra  EI30 and QR for storm sequence Erodibilities associated with EI30

  7. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra  Erodibilities associated with EI30 Predicted event soil loss The product of QR and KUM produces similar results to RUSLE2 Ks when applied RUSLE2 storms

  8. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra

  9. Runoff as a factor in USLE/RUSLE TechnologyP.I.A. Kinnell, Institute for Applied Ecology, University of Canberra

More Related