360 A NATIONAL PLAN FOR AMERICAN FORESTRY 



lands are totally unprotected has an important influence in promoting 

 a high run-off ratio. This in turn is reflected in floods, soil erosion, 

 and decreased ground water supplies, especially in the more arid and 

 sparsely vegetated portions of the basin. 



STREAMFLOW PROBLEMS 



CHARACTER OF FLOW 



The streams of the basin are in the main perennial. In western 

 Texas the headwater tributaries of the Brazos and Colorado Rivers 

 are, however, dry for large portions of the year. The greatest range 

 in flow is found in arid regions of torrential rainfall in central and 

 western Texas. According to records of the Geological Survey the 

 Little River, a tributary of the Brazos, had a maximum daily flow 

 over a 14-year period of 647,000 second-feet and a minimum flow of 

 only 3 second-feet. The Brazos River at Mineral Wells, Tex., has 

 been completely dry on several occasions during the last 6 years and 

 has had a maximum daily flow of 95,600 second-feet. The Colorado 

 River at Austin, Tex., has varied over a 32-year period from 151,000 

 to 13 second-feet. 



On the other hand, the Sabine River, draining a catchment basin 

 having heavy rainfall and forests covering approximately 43 percent 

 of the total area, fluctuates far less than the streams draining more 

 arid con try, varying over a 6-year period at Ruliff, from 61,200 to 

 372 second-feet. 



FLOODS 



Floods are relatively common in all the drainages. In the Brazos 

 and Colorado River drainages in central and western Texas, severe 

 floods have been occurring at least once in a decade, caused as a rule by 

 local rains of high intensity and rendered doubly destructive because 

 of the lack of an adequate cover on the watersheds. The flood of 1900 

 caused the failure of the Austin Dam on the Colorado River and 

 flooded large areas of bottomland from Austin to the Gulf. The 

 Brazos flood of September 1921 is reported to have cost the lives of 

 164 people and damaged property to the extent of more than 

 $12,000,000. 



Floods are even more common in the Trinity River drainage, 

 occurring most frequently during spring and fall. According to 

 Weather Bureau records, overflows in the vicinity of Dallas, Tex., 

 have averaged about 4 a year during the last 8 years, and the 

 Trinity River at Trinidad, Tex., has been at flood 33 times in the last 

 8 years. Both of the above stations are located in the black waxy 

 belt a region of heavy but productive soils practically all of which 

 are in cultivation. On the Sabine River floods occur almost annually, 

 but they are seldom general throughout the drainage and are most 

 frequent during the winter months as the result of heavy rains of 

 rather local occurrence. 



STREAM-FLOW UTILIZATION 



The streams of the West Gulf Basin are and apparently must be 

 relatively unimportant for navigation and the development of hydro- 

 electric power, owing largely to uncertain flow and heavy silt loads. 



