You are asked to assess the erosion rate of a catchment. The granitic rocks are essentially uniform within the catchment, which has a map area of 32 km². The sediment transport rate, averaged over 30 years of gauging records, is 1.9x10⁶ kg/yr. 

• Calculate the average erosion rate of the catchment over this time scale, reporting it in both microns/year and mm/ka (ka = thousands of years, kilo-annum), and in tonnes/km²/yr (recall that 1 tonne = 10³ kg). Please be sure to describe all the assumptions you are making in this analysis.