(a) Determine the cumulative abstractions for the Austin, Texas, 25-year design storm given below, for SCS curve numbers of 75 and 90. Use the NRCS (SCS) method and plot these two curves of cumulative abstractions on one graph. (b) Also compute the cumulative excess rainfall vs. time, and the excess rainfall hyetograph for each curve number. Plots the excess rainfall hyetographs for the two curve numbers on one graph. Design storm rainfall depths (in) 30 40 50 60 70 80 90 100 . Minutes 10 20 10-year 0.070 0,083 0.104 0.126 0.146 0.170 0.250 0.450 1.250 0.650 25-year 0.105 0.122 0.140 0.167 0.173 0.225 0.306 0.510 1.417 0.783 100-year 0.138 0.155 0.168 0.203 0.250 0.332 0.429 0.665 1.700 0.935 Minutes 110 120 130 140 150 160 170 180 Totals 10-year 0.317 0.203 0.164 0.142 0.112 0.093 0.073 0.067 4.470 25-year 0.417 0.297 0.192 0.170 0.143 0.126 0.119 0.099 5.511 100-year 0.513 0.373 0.293 0.243 0.182 0.159 0.147 0.135 7.020