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<br />Forest-Fire Devegetation and Basin Adjustments <br /> <br />runoff and sediment to the stream system: (1) steep. headwater basins deve- <br />loped on the caldera rim (Apache Spring area); (2) steep, side-valley water- <br />sheds developed on the Frijoles Canyon walls (not studied); and (3) moderate <br />relief watersheds developed on the meSa tops above Frijoles Canyon (Burnt <br />Mesa area). All these watershed types were devegetated by forest-fires. <br />Mesa-top watersheds have larger drainage areas than inner canyon water- <br />sheds. and more sediment and runoff are provided from these areas to Rita <br />de 105 Frijoles. <br /> <br />Low-order drainage basins of Burnt Mesa and Apache Springs differ in <br />their geomorphic character (table 1). Drainage basins of the Burnt Mesa <br />area are typically elongate due to their development on gently sloping mesa <br />tops. The Apache Springs basins are characteristically circular due to their <br />development on valley side-slopes of incised trunk-drainage lines (table 1). <br />The largest drainage basin investigated is an intense-burn third-order basin <br />of Burnt Mesa which cOVers 4116.5 m2 (fig. 3). The smallest basin investig- <br />ated is the light-burn. first-order basin of the Apache Springs at'ea which <br />covers 280 mZ. Drainage basins of the Apache Springs area are steeper and <br />shorter than those on Burnt Mesa. Relief in the drainage basins is similar <br />in both areas (table 1), <br /> <br />GEOMORPHIC MAP OF INTENSE- BURN WATERSHED, BURNT MESA <br /> <br />" <br /> <br />O'\onnel. dashed where wide ===:::~ <br />dash. dat where narrow _..-., <br />Alluvium d9 <br />Scoured ChaMel ~ <br />Hillslape <br />Rills <br />-...... <br />Contour lntervol . 2 teet <br /> <br /> <br />tn, <br />20 <br /> <br />40 <br />, <br /> <br />12 <br /> <br />FXPI ANATION <br /> <br />20 <br /> <br />'."","1 <br />UnPCItterned <br /> <br />Special Features <br />Root burn depressions #.:0 <br />Upraaf.d fro mounds' ~~ <br />SCQrps u..... <br />A,B,C Erasklnpintransects- <br />b,c,d,' Qloln tronsects <br /> <br />Sediment TrQp ST <br /> <br />28 <br /> <br />Figure 3. Geomorphic map of the intense-burn watershedl Burnt Mesa. The map <br />shows the extent of rilling versus sheetwash as of July, 1978. <br />Also shown are the erosion-pin transect and sediment-trap loca- <br />tions. <br /> <br />,n, <br />