\bibitem{abrahams}
Abrahams, A.D., Channel link density and ground slope, {\it Ann. Assoc. Am. 
Geog., 70}, 80-93, 1980.
\bibitem{abrahams}
Abrahams, A.D., and J.J. Ponczynski, Drainage density in relation to precipitation
intensity in the U.S.A., {\it J. Hydrol., 75}, 383-388, 1984.
\bibitem{beven}
Beven, K.J., and M.J. Kirkby, A physically based, variable contributing 
area model of basin hydrology, {\it Hydrol. Sci. Bull., 24}, 43-69, 1979.
\bibitem{bryan}
Bryan, R., Processes and significance of rill development, in {\it Rill Erosion:
Processes and Significance}, edited by R. Bryan, Catena Suppl., 8, 1-15, 1987.
\bibitem{bryan}
Bryan, R.B., and J. Poesen, Laboratory experiments on the influence of slope
length on runoff, percolation and rill development, {\it Earth Surf. Proc.
Land., 14}, 211-231, 1989.
\bibitem{cerda}
Cerda, A., and P. Garcia-Fayos, The influence of slope angle on sediment,
water and seed losses on badland landscapes, {\it Geomorphology, 18}, 77-90, 1997.
\bibitem{dietrich}
Dietrich, W.E., C.J. Wilson, D.R. Montgomery, J. McKean, and R. Bauer,
Erosion thresholds and land surface morphology, {\it Geology, 20}, 675-679,
1992.
\bibitem{dietrich}
Dietrich, W.E., C.J. Wilson, D.R. Montgomery, and J. McKean, Analysis of erosionthresholds, channel networks, and landscape morphology using a digital terrain
model, {\it J. Geol., 101}, 259-278, 1993.
\bibitem{fernandes}
Fernandes, N., and W.E. Dietrich, Hillslope evolution by diffusive processes:
The timescale for equilibrium adjustments, {\it Water Resour. Res., 33},
1307-1318, 1997.
\bibitem{govers}
Govers, G., Spatial and temporal variability in rill development processes at
the Huldenberg experimental site, in {\it Rill Erosion}, edited by R. Bryan,
pp. 17-34, Catena Verlag, Cremlinger, West Germany, 1987.
\bibitem{govers2}
Govers, G., Relationship between discharge, velocity and flow area for rills
eroding loose, nonlayered materials, {\it Earth Surf. Proc. Land., 17}, 515-528, 1992.
\bibitem{hairsine}
Hairsine, P.B., and C.W. Rose, Modeling water erosion due to overland flow using
physical principals, 2. Rill flow, {\it Water Resour. Res.}, 237-243, 1992.
\bibitem{hanks}
Hanks, T.C., R.C. Buckman, K.R. Lajoie, and R.E. Wallace, Modification
of wave cut and faulting-controlled landforms, {\it J. Geophys. Res, 89},
5771-5790, 1984.
\bibitem{hanks}
Hanks, T.C., and R.E. Wallace, Morphological analysis of the Lake Lahontan
shoreline and beachfront fault scarps, Pushing County, Nevada, {\it Bull. Seismol.
Soc. Am., 75}, 835-846, 1985.
\bibitem{harvey}
Harvey, A.M., Process interactions, temporal scales and the development
of hillslope gully systems: Howgill Fells, northwest England, {\it Geomorphology,
5}, 323-344, 1992.
\bibitem{heimsath}
Heimsath, A.M., W.E. Dietrich, K. Nishiizumi, and R.C. Finkel, The soil production
function and landscape equilibrium, {\it Nature, 388}, 358-361, 1997.
\bibitem{horton}
Horton, R.E., Erosional development of streams and their drainage basins:
Hydrophysical approach to quantitative morphology, {\it Bull. Geol. Soc. Am.,
56}, 275-370, 1945.
\bibitem{hovius}
Hovius, N., Regular spacing of drainage outlets from linear mountain belts,
{\it Basin Res., 8}, 29-44, 1996.
\bibitem{imeson}
Imeson, A.C., and J.M. Verstraten, Rills on badland slopes: A physico-chemicallycontrolled phenomenon, {\it Catena, 12}, suppl., 139-150, 1988.
\bibitem{jyotsna}
Jyotsna, R., and P.K. Haff, Microtopography as an indicator of modern hillsope 
diffusivity in arid terrain, {\it Geology, 25}, 695-698, 1997.
\bibitem{kashiwaya}
Kashiwaya, K., On the rill net in a slope system, {\it Bull. Disaster Prev.
Res. Inst. Kyoto Univ., 28}, 69-93, 1978.
\bibitem{kashiwaya}
Kashiwaya, K., A study of rill development process based on field experiments,
{\it Geogr. Rev. Japan, 53}, 419-434, 1980.
\bibitem{kirkby}
Kirkby, M.J., Hillslope process-response models based on the continuity equation,
in {\it Slopes, Forms, and Processes}, Institute of British Geographers Spec. Pub.
No. 3, 1971.
\bibitem{kirkby}
Kirkby, M.J., A two-dimensional simulation model for slope and stream evolution,
in {\it Hillslope Processes}, edited by A.D. Abrahams, Allen and Unwin, London,
pp. 203-222, 1986.
\bibitem{kenyon}
Kenyon, P.M., and D.L. Turcotte, Morphology of a delta prograding by bulk
sediment transport, {\it Geol. Soc. Am. Bull., 96}, 1457-1465, 1985.
\bibitem{lei}
Lei, T., M.A. Nearing, K. Haghighi, and V.F. Bralts, Rill erosion and morphological
evolution: A simulation model, {\it Water Resour. Res., 34}, 3157-3168, 1998.
\bibitem{loewenherz}
Loewenherz, D.S., Stability and the initiation of channelized surface drainage:
a reassessment of the short-wavelength limit, {\it J. Geophys. Res., 96}, 8453-8464, 1991.
\bibitem{loe}
Loewenherz-Lawrence, D.S., Hydrodynamic description for advective sediment transport
processes and rill initiation, {\it Water Resour. Res., 30}, 3203-3212, 1994.
\bibitem{mckean}
McKean, J.A., W.E. Dietrich, R.C. Finkel, J.C. Southon, and M.W. Caffee, Quantification
of soil production and downslope creep rates from cosmogenic $^{10}$Be accumulations
on a hillslope profile, {\it Geology, 21}, 343-346, 1993.
\bibitem{mitchell}
Mitchell, N.C., Diffusion transport model for pelagic sediments on the Mid-Atlantic
Ridge, {\it J. Geophys. Res., 100}, 19991-20009, 1995.
\bibitem{montgomery}
Montgomery, D.R., and W.E. Dietrich, Where do channels begin?, {\it Nature,
336}, 232-234, 1988.
\bibitem{montgomery}
Montgomery, D.R., and W.E. Dietrich, Source areas, draianage density, and
channel initiation, {\it Water Resour. Res., 25}, 1907-1918, 1989.
\bibitem{montgomery}
Montgomery, D.R., and W.E. Dietrich, Channel initiation and the problem of
landscape scale, {\it Science, 255}, 826-830, 1992.
\bibitem{montgomery}
Montgomery, D.R., T.B. Abbe, J.M. Buffington, N.P. Peterson, K.M. Schmidt,
and J.D. Stock, Distribution of bedrock and alluvial channels in forested
mountain drainage basins, {\it Nature, 381}, 587-589, 1996.
\bibitem{mosley}
Mosley, M.P., {\it An experimental study of rill erosion}, MSc. thesis,
Colorado State Univ., Fort Collins, CO, 1972.
\bibitem{moseley}
Moseley, M.P., Rainsplash and the convexity of badland divides, {\it Z.
Geomorphol. Suppl., 18}, 10-25, 1973.
\bibitem{nash}
Nash, D.B., Forms of bluffs degraded for different lengths of time in
Emmet County, Michigan, USA, {\it Earth Surf. Processes, 5}, 331-345, 1980.
\bibitem{patton}
Patton, P.C., and S.A. Schumm, Gully erosion, Northwestern Colorado: A thresholdphenomenon, {\it Geology, 3}, 88-90, 1975.
\bibitem{peckham2}
Peckham, S.D., RiverTools 1.01, electronic software, available at
http://cires.colorado.edu/people/peckham.scott/RT.html, 1997.
\bibitem{phillips}
Phillips, B.C., and A.J. Sutherland, Diffusion models applied to channel degradation,
{\it J. Hyd. Res., 25}, 179-191, 1986.
\bibitem{phillips}
Phillips, L.F., and S.A. Schumm, Effect of regional slope on drainage networks,
{\it Geology, 15}, 813-816, 1987.
\bibitem{pierce}
Pierce, K.L., and S.M. Colman, Effect of height and orientation (microclimate)
on geomorphic degradation rates and processes, late-glacial terrace scarps
in central Idaho, {\it Bull. Geol. Soc. Am., 97}, 869-885, 1986.
\bibitem{roering}
Roering, J.J., J.W. Kirchner, and W.E. Dietrich, Evidence for
nonlinear, diffusive sediment transport and implications for landscape morphology,
{\it Water Resour. Res., 35}, 853-870, 1999.
\bibitem{schumm}
Schumm, S.A., Evolution of drainage systems and slopes on badlands at
Perth Amboy, New Jersey, {\it Geol. Soc. Am. Bull., 67}, 597-696, 1956.
\bibitem{schumm}
Schumm, S.A., M.P. Mosley, and W.E. Weaver, {\it Experimental Fluvial Geomorphology},
Wiley Interscience, New York, 1987.
\bibitem{smith}
Smith, T.R., and F.P. Bretherton, Stability and the conservation of mass in
drainage basin evolution, {\it Water Resour. Res., 8}, 1506-1529, 1972.
\bibitem{smith}
Smith, T.R., and G.E. Merchant, Conservation principles and the initiation of
channelized surface flows, in {\it Natural and Anthropogenic Influences in Fluvial
Geomorphology}, Geophysical Monograph 89, American Geophysical Union, Washington,
D.C., pp. 1-25, 1995.
\bibitem{talling}
Talling, P.J., M.D. Stewart, C.P. Stark, S. Gupta, and S.J. Vincent,
Regular spacing of drainage outlets from linear fault blocks, {\it Basin
Res., 9}, 275-302, 1997.
\bibitem{tarboton}
Tarboton, D.G., R.L. Bras, and I. Rodriguez-Iturbe, A physical basis for drainage
density, {\it Geomorphology, 5}, 59-76, 1992.
\bibitem{tucker}
Tucker, G.E., and R.L. Bras, Hillslope processes, drainage density, and landscape
morphology, {\it Water Resour. Res., 34}, 2751-2764, 1998.
\bibitem{vandaele}
Vandaele, K., J. Poesen, G. Govers, and B. van Wesemael, Geomorphic threshold
conditions for ephemeral gully incision, {\it Geomorphology, 16}, 161-173, 1996.
\bibitem{wallace}
Wallace, R.E., Profiles and ages of young fault scarps, north-central
Nevada, {\it Geol. Soc. Am. Bull, 88}, 1267-1281, 1977.