SURFACE CONDITIONS AND STREAM FLOW 



375 



"The total stand of timber on this part 

 of the Cumberland watershed is 6,212,531,- 

 000 board feet. It is being cut away by- 

 lumbering alone at the rate of 4 per cent 

 a year. These figures show that timber is 

 disappearing on account of lumber opera- 

 tions eight times as fast as it is removed 

 to clear land for farming purposes. In 

 other words, supposing that lumbermen 

 would cut clear as they go, 8 acres would 

 be stripped for timber to 1 cleared for agri- 

 culture. The forest is not being cut clear. 

 Instead, the lumberman is going over it 

 time after time, picking out the particular 

 kinds or classes of timber that he wants. 

 First, he took the walnut and cherry; next, 

 the white oak and poplar; now he is taking 

 the chestnut and other kinds of oak. At 

 the present time few tracts can be found 

 from which one or more of the valuable tim- 

 bers have not been culled. Other tracts 

 have been stripped of nearly their entire 

 growth. 



"At intervals of from one to five or six 

 years fires run through the woods on the 

 hills and mountains where the Cumberland 

 River has its source. The fires are more 

 frequent and destructive in districts where 

 part of the timber has been cut and the 

 refuse left on the ground. The dry ridges 

 burn oftener than the coves, because the 

 latter are sometimes too damp for burning. 

 In times of prolonged drought, however, 

 fires run through the ravines and coves 

 where the densest growth is found. The 

 fires are usually slow, and the damage to 

 mature timber is not great, but the injury 

 to the young growth is frequently exces- 

 sive, and soil damage is serious. As a 

 rule all seedlings and sprouts less than 

 four or five feet high are killed, and, since 

 fires come at intervals so frequent that the 

 young growth can not attain a size above 

 that, a large part of what would be the 

 future forest, as well as the present ground 

 cover, is destroyed. The surviving stand 

 thus becomes thinner year by year, since it 

 can not be replenished by young growth, 

 and since the mature trees are steadily 

 falling by natural decay or by the ax. 



"Though the fires are slow and small, 

 they burn the leaf cover and the upper 

 layers of humus at each visitation. This 

 removes or injures the porous surface, one 

 of whose essential functions is to arrest 

 the storm water falling upon the slopes 

 and afford it an opportunity to sink into 

 the ground. With the packing of the sur- 

 face, after the litter and humus have been 

 burned away, the water flows down the 

 slopes and quickly reaches the streams, 

 where, if in sufl5cient quantity, it pro- 

 duces flood conditions. Low water follows, 

 because the hard ground is able to take in 

 but little of the storm water to be paid out 

 slowly afterward. 



"The behavior of the Cumberland River 

 shows a direct and positive relation be- 

 tween the run-off and the changed condi- 



tion of the surface. The changes due to 

 agriculture and lumbering can be definitely 

 stated, but the extent and effect of forest 

 fires are not subject to exact calculation. 

 Yet undoubtedly all of these influences are 

 active in producing the results as shown in 

 the flood and low water records at Burn- 

 side. It is impossible that these results 

 should be due to rainfall, because the rain- 

 fall was approximately 10 per cent less in 

 the second half of the period. Since no 

 other Influences could have produced the 

 result, there is no conclusion possible other 

 than that the progressive floods and low 

 waters have been due to the changes ac- 

 complished on the surface of the water- 

 shed. 



A Watershed Where .Conditions Have 

 Grown Better 



"The fact that man by his operations 

 may decidedly change the regimen of a 

 river is shown not alone by those streams 

 whose flow has been influenced by clearing 

 away the forest. It is shown, on the other 

 hand, by streams whose watersheds of 

 prairie soil compacted for ages by the 

 trampling of buffalo, and more recently by 

 cattle of the great ranches of the West, 

 have been to a large extent brought under 

 cultivation. 



"A stream which shows this tendency in 

 an unmistakable way is the Red River, 

 which forms the boundary for many miles 

 between Texas and Oklahoma. On this 

 stream records of flow are available for 

 sixteen years. The number of floods in 

 the first half of this period was 19; in the 

 second half, 16. The number of days of 

 flood in the first half was 87; in the second 

 half, 60. Considering also the low-water 

 periods of this river, we find that in the 

 first half of the period there were 49 pe- 

 riods of low water; in the second half there 

 were 8. In the first half the duration of 

 low water was 826 days; in the second 

 half, 208 days. A falling off in the rain- 

 fall occurred on this watershed, there being 

 1.94 inches less water per year in the sec- 

 ond than in the first. Its drainage basin 

 is, and has been during the time of its 

 known history, practically without forests, 

 only 1 acre in 10 being forested. In that 

 respect it differs from all eastern and 

 many western rivers whose basins are 

 more extensively forest covered. 



"Why has the Red River constantly 

 changed its flow toward steadiness and uni- 

 formity, while many other rivers have 

 changed in exactly the opposite direction? 

 The area of the Red River drainage basin 

 above Arthur City, Tex., where the rec- 

 ords were made, is 40,200 square miles, di- 

 vided almost equally between Oklahoma 

 and Texas. In this river, as in those be- 

 fore mentioned, the geology and topogra- 

 phy have not changed. The precipitation 

 has changed considerably in the direction 

 of lessened rainfall, but not enough to ac- 



