VALLEY FILLING BY INTERMITTENT STREAMS 



A. E. PARKINS 



Michigan State Normal College, Ypsilanti, Mich. 



Streams having steep grades are usually thought to be in active 

 vertical erosion. The writer finds, however, that many inter- 

 mittent streams are not degrading but are actively aggrading 

 parts or all of their valleys. One of the best examples of such 

 valley filling is that of Jewell's Creek, described in this article. 



This little valley is found on the right bank of the Huron River 

 about two miles above the city of Ypsilanti. The Ann Arbor 

 sheet (U.S.G.S.) shows it as a mere ravine to the west of the little 

 settlement of Superior. The accompanying map shows that the 

 valley is about eight hundred and fifty feet long and that the head- 

 waters are eighty-five feet above the Huron River. The line mark- 

 ing the west boundary of the map is on the line of a fence. The 

 land to the west is under cultivation. The main stream has two 

 tributaries, one from the southwest which enters near the mouth, 

 and another from the northwest, joining the main stream near the 

 head waters. Both of these branches head into cultivated fields. 



The main valley is divided into two distinct parts. Above 

 where the forty-five-foot contour line crosses the valley, the flow 

 of the water is intermittent. The floor is thereby mostly dry and 

 covered with a species of grass that can live under dry conditions 

 for part of the year. Below the forty-five-foot contour line the 

 flow of water is constant throughout the year. Here the bottom 

 is mostly wet and covered with swamp grass, which greatly retards 

 the flow of water. Fig. 2, taken from a point near the mouth, 

 gives a good idea of the lower part of the valley; while Fig. 3 gives 

 a view of the middle portion just above the crossing of the forty- 

 five-foot contour. The stump shown in the face of the small cliff 

 in the foreground is indicated on the map by the letter S, the trees 

 are indicated by circles, and the cattle are standing just about 

 where the fifty-foot contour line crosses the flat bottom of the 



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