Liverpool to Havana

Richardson finds the changes in the section of the Illinois River between Liverpool and Havana to be even more significant than the section between Chillicothe and Peoria Lake. Liverpool is 34 miles below the foot of Peoria Lake, and Havana is 42 miles below this same point.

In 1915, the mud has a “wholesome earthy order in midsummer” except below fish markets and large drains. In 1920, however, the muds from the deeper channel near Hogfat Bend, three miles above Havana are “distinctly foul-smelling,” and hundreds of large gas bubbles rise to the surface when the sampler hits the bottom. These samples show the same spongy texture previously mentioned regarding the muds from the Chillicothe area.

The most significant changes that Richardson finds in this section of the river from 1915 to 1920 include: the disappearance of five out seven families of snails; over a half dozen species of bottom-fauna larval midges; and 12 out of 13 of “other insects, worms, small Crustacea, and other small bottom-invertebrates” (Table 7). Snails are the most seriously impacted in numbers, bulk, and weight.

Table 7: Snail Fauna of Bottom Muds, Liverpool to Havana, 1913-15 to 1920 (Richardson 1920)

The most significant change in the Chironomidae is the disappearance of half dozen of the more sensitive species and the appearance of the pollution tolerant Chironomus plumosus Linn., which also invaded the Chillicothe to Peoria Lake section earlier. Sludge-worms also show an almost perpendicular rise from none at all in this section. Table 8 shows the average numbers per square yard for clams found in the Illinois River from Liverpool to Havana in 1913-15 compared with 1920.

Table 8: All Small Bottom-Animals, Liverpool to Havana, 1915 and 1920 (Richardson 1920)