『Abstract
　Current theories regarding the connections and feedbacks between surface and tectonic processes are predicated on the assumption that higher rainfall causes more rapid erosion. To test this assumption in a tectonically active landscape, a network of 10 river monitoring stations was established in the High Himalayas of central Nepal across a steep rainfall gradient. Suspended sediment flux was calculated from sampled suspended sediment concentrations and discharge rating curves. Accounting for solute and bedload contributions, the suspended sediment fluxes were used to calculate watershed-scale erosion rates that were then compared to monsoon precipitation and specific discharge. We find that, in individual watersheds, annual erosion rates increase with runoff. In addition, our data suggest average erosion rate increases with discharge and precipitation across the entire field site such that the wetter southern watersheds are eroding faster than the drier northern watersheds. The spatially non-uniform contemporary erosion rates documented here are at odds with other studies that have found spatially uniform long-term rates (10⁵ - 10⁶ yr) across the pronounced rainfall gradient observed in the region. The discrepancy between the modern rates measured here and the long-term rates may be reconciled by considering the high erosional efficiency of glaciers. The northern catchments were much more extensively glacierized during the Pleistocene, and therefore, they likely experienced erosion rates that were significantly higher than the modern rates. We propose that, in the northern watersheds, the high rates of erosion during periods of glaciation compensate for the low rates during interglacials to produce a time-averaged rate comparable to the landslide-dominated southern catchments.

Keywords: Himalayas; Nepal; erosion; suspended sediment; climate』

Table 1 Watershed attributes and rates

Site no.a	Area (km2)	Mean elev. (m)	Mean slope (deg)	Average reliefb (m)	Runoff (m/yr)	％ Area glacierized	Average erosion rate, (range) (mm/yr)c	Record length (yr)
1 - Koto	812	4794	30	1076	0.76	12	1.0 (0.7-1.3)	4
2 - Nar Khola	1052	5174	28	909	0.15	10	0.1 (0.1-0.2)	3
3 - Temang Khola	21	4087	29	1070	1.62	0	0.1 (0.1-1.9)	2
4 - Danaque Khola	7	3349	32	442	1.17	0	1.0 (0.0-1.9)	2
5 - Upper Dharapani	1946	4918	26	886	0.56	11	0.4 (0.4-0.4)	3
6 - Dudh Khola	491	4694	32	1147	0.67	15	0.3 (0.2-0.5)	4
7 - Dona hola	89d	4851	32	1117	1.09	0d	0.4 (0.2-0.7)	3
8 - Lower Dharapani	2605	4870	27	947	0.44	12	0.5 (0.4-0.5)	2
9 - Bhulbule	3217	4522	28	958	0.76	10	0.5 (0.4-0.6)	3
10 - Khudi Khola	152	2566	26	862	3.54	0	2.0 (1.5-3.0)	5
a Keyed to site nos. in Fig. 1. b Relief determined over a 1-km radius moving window. c Total erosion rate includes estimated bedload and measured solute load contributions. d A proglacial lake traps sediment issuing from the upper reaches of the catchment; the value shown here is the drainage area below the lake and is the area used for the erosion rate calculation. The entire catchment is 155 km2 and 21％ of that area is glacierized.

1. Introduction
2. Material and methods
　2.1. Field site
　2.2. Measurements
　2.3. Discharge calibration
3. Results
　3.1. Error analysis
　3.2. Erosion rates
4. Discussion
　4.1. Controls on modern erosion rates
　4.2. Modern erosion rates vs. long-term erosion rates
5. Conclusion
Acknowledgments
References