400 
both increased velocities and increased flood volumes retard sedimen- 
tation and keep the summit of the bar lower than in the other two cases. 
Lake and other backwater acreage per mile between Havana and 
the Lagrange dam (382.4 acres) exceeded at the low water of 1901 that 
of any other reach of river except the 16.8 miles between Copperas 
Creek dam and Havana.* The densest distribution of pond acreage oc- 
curs in the 9 miles between the foot of Grand Island and the mouth of 
the Sangamon and falls within the boundaries of greatest channel 
depths, least flood velocity, softest and darkest-colored bottom deposits, 
and richest bottom fauna, as shown by our collections of 1915. 
WiptHs AND DepTHs, Havana To Lagrance Dam, Low Water, 1901 
Miles 
1. Havana to foot of 
Grand Island. Shal- 
2. Foot of Grand Island 
to Browning. Nar- 
row, deep section 
3. Browning to Lagrange 
dam. Wide, shallow 
, * Depth, ft. 
above Station Width, ft. 
Grafton mar 
119.0 1 mile below Havana 658 8.5 
DUS TM) ate mts cB euaicicde eee eters 768 8.7 
PUES WEN ors cee amech oeexe eee 549 10.7 low section 
DT 620 ifs hae an ee eee 640 10.0 
ALD OS Ped Soc: crevor ottermr ners oc eto 530 12.5 
LAU SEER. AN Be Ree 732 8.3 
113.5 Head of Grand Island 712 9.0 
TLIO halls sive Sad deka seeped pas 457 91 
DAOO ig erates Wier won sheleraig at arceets aes ge) West channel only 
LOSO S| oyeran te trate ernie teas 11.0 
106.5 1/3 mile above foot 
‘ of Grand Island.... 514 14.7 
106.2 Foot of Grand Island 658 12.4 
a CU UN eet eee es an Th 475 18.4 
102.8 Sheldon’s Grove...... 582 15.6 
oe es Aree ee ator eecioio otek 439 20.4 
98.0 Mouth of Sangamon.. 
98:2) Al gato fuaceaghn tine feos 17.0 
97.0 1/4 mile below Brown- 
BOE ve aesaiecasrepee eee 494 13.4 
95.7 1% miles below 
Brownie ecioateiee 878 8.7 section 
OB iO} Aly is chances Bes ay SMe SeteR SS 750 8.3 
UIE MEN| eins Neng ete nese te mae 732 10.2 
Roe ti selena nay thay I ly odio 658 13.2 
88.2 1/4 mile below wagon 
bridge, Beardstown ae 12.8 
SG i 21 (Alay eee ers ee ae ee 1,006 10.2 
Ly Tt en PPI ASI eat oR AR ri 1,000 13.1 
SIGS Ne ciate ster sere seen. eee ee 514 12.1 
55) Hill esc ei ere Bete aA 841 8.5 
SUB O| EROe Ss See ce canned 732 10.5 
LUPE Sia a Bee a eres ns Flee 732 11.7 
18:85, allele ts eee ae ee eee amb 15.0 
T8L6 |) crag ye apttevese i s.scegetteo totes 805 11.8 
77.7 250 yards above La- 
grange dam ...... 933 11.7 
* Table, p. 378. 
