Quarterly Progress Report August 2004
Highland Silver Lake Watershed (ROZA)
Limno-Tech, Inc. Page 23
Urbanization and growth
Urbanization and growth are two factors that can affect the amount and quality of runoff
from land surfaces and which also affect the demand on water and sewage treatment
facilities. The Highland Silver Lake watershed encompasses portions of two rural
counties and four small communities. 77% of the watershed is located in Madison
County and 23% is located in Bond County. The four communities are Highland,
Grantfork, New Douglas and Old Ripley. The City of Highland is the largest urbanized
area in the watershed, with a population of 8,500 residents (City of Highland website).
This city is only partially contained in the Highland Silver watershed.
Table 6 indicates that population growth in Madison County has been slow (3%) between
1990-2000, while it has been more rapid in Bond County (~18%). Anecdotal information
from area residents suggest that there is a significant amount of new residential
development near the upper part of the lake that are serviced by septic systems.
Population projections available in a State of Illinois (1997) report project Bond County
to decrease in population by 2020 and for Madison County to increase by 5% between
2000 and 2010 and by another 5% between 2010 and 2020 (Table 5). Based on the
growth observed from the U.S. Census data for Bond County (~18% between 1990-
2000), it appears that the population projections for 2010 and 2020 are no longer valid.
Table 6. Bond and Madison County population
County 19901 20001 20102 20202
Bond 14,991 17,633 16,917 16,908
Madison 249,238 258,941 271,091 285,126
1U.S. Census Bureau
2State of Illinois, 1997
Point sources and water withdrawal
Point sources and water withdrawals may affect water quantity and quality in Highland
Silver Lake. Two NPDES-permitted dischargers are located within the Highland Silver
Lake watershed. One is the Highland Water Treatment Plant, which has a permit
(IL0001112) to discharge treated filter backwash and settling lagoon overflow to
Highland Silver Lake. The other is the Munie Trucking Company, which has an expired
permit (IL0068861) for pit pumpage and stormwater. There are also three locations in the
watershed where there are one or more oil wells. One landfill (Bertha Davis, ID
50200001) was also identified within the watershed. The locations of the water treatment
plant, Munie Trucking Company, the oil wells and the landfill are shown on Figure 1.
The Highland Water Treatment Plant mentioned previously, also has a permit to
withdraw and treat surface water from Highland Silver Lake (Facility No. IL1190550).
This water is supplied to Highland, St. Jacob, Grantfork and Pierron. The average daily
process produces 1.2 million gallons per day (MGD) with a total design capacity of 4.2
MGD (City of Highland Water Treatment Plant website,
http://www.ci.highland.il.us/Public_Documents/HighlandIL_Treatment/index).
