Quarterly Progress Report August 2004
North Fork Kaskaskia River Watershed
Limno-Tech, Inc. Page 10
The following sections provide a broad overview of the characteristics of the North Fork
Kaskaskia River watershed.
Soils and topography
Information on soils and geology was compiled in order to understand whether the soils
are a potential source of manganese, iron and phosphorus. Printed copies of the county
soil surveys were obtained from the County NRCS District Conservationists for Clinton,
Marion and Fayette Counties. The electronic STATSGO soils were also obtained. The
STATSGO soils information was used to identify the predominant soil associations in the
North Fork Kaskaskia River watershed and the Marion County soil survey (Miles, 1996)
was then used to describe these soils. STATSGO soils for the North Fork Kaskaskia
River watershed are shown in Figure 2 and summarized in Table 2. As discussed below,
many of the soils in the North Fork Kaskaskia River watershed contain manganese and
iron oxide concretions or accumulations and are also acidic. This could result in
manganese and iron moving into solution and being transported in base flow and/or
runoff. Furthermore, some of the soils described below (e.g., Hoyleton, Darmstadt,
Bluford and Hickory) also are found on the short side slopes along drainageways, thus
facilitating the transport of the manganese into waterbodies through streambank or lake
shore erosion. The acidic nature of the soils may contribute to the low pH observed in
the North Fork Kaskaskia River.
Fifty-five percent of the North Fork Kaskaskia River watershed is underlain by the Cisne-
Hoyleton-Darmstadt association. The Cisne series consists of poorly drained, very
slowly permeable soils on the broad, nearly level parts of the Illinoian till plain. These
soils formed in loess and in the underlying loaming sediments, with slopes ranging from
0 to 2 percent. At depths of 8 to 30 and 50 to 60 inches, medium and fine rounded dark
accumulations of iron and manganese oxide are noted. The Cisne soil series is also
described as being strongly to very strongly acid. The Hoyleton series consists of
somewhat poorly drained, slowly permeable soils on knolls and low ridges or on short
side slopes along drainageways on the Illinoian till plain. Slopes range from 0 to 7
percent. Common medium irregular dark stains of iron and manganese oxide are noted at
depths of 30-50 inches and these soils are neutral to very strongly acid. The Darmstadt
series consists of somewhat poorly drained, very slowly permeable soils on low ridges or
on short side slopes along drainageways on the Illinoian till plain. Slope ranges from 0 to
6 percent. Common fine and medium rounded dark nodules of iron and manganese oxide
are noted at all depths of the Darmstadt series and the pH in these soils varies from
strongly alkaline to medium acid.
Forty-five percent of the North Fork Kaskaskia River watershed is underlain by the
Bluford-Ava-Hickory association. The Bluford series consists of somewhat poorly
drained, slowly permeable soils on low ridges, broad ridgetops or short side slopes along
drainageways. Slopes range from 0 to 7 percent. Rounded dark nodules or iron and
manganese oxide are noted at all depths in the Bluford series, with these soils described
as being extremely acid to neutral in pH. The Ava series consists of moderately well
drained soils on side slopes, the crest of prominent ridges and narrow ridgetops on the
Illinoian till plain. Slopes range from 1 to 10 percent. Fine and medium rounded nodules
or irregular dark accumulations of iron and manganese oxide are noted at all depths of the
