Water Pollution - Threats to the Old Reservation

High ground water levels and other conditions create concern regarding the potential for ground water contamination on the lower Reservation. The conditions that pose the greatest threat are historical solid waste/hazardous waste accumulation, surrounding agricultural land use, residential septic systems, and abandoned residential wells. Additionally, it is possible that pollutants carried in McNulty Slough, which passes within 40 yards of the lower Reservation and may cause salt-water intrusion into the Tribe’s drinking water source, could impact the Tribe’s groundwater.

The prominent concern is the historical existence of open dumps and burn ash pits on the old Reservation. While many open dumps, burn ash pits, abandoned vehicles, etc., were removed during a major cleanup effort in 2002 (a collaboration between the Tribe and California Integrated Waste Management Board), ongoing illegal dumping is an on-going problem at the old Reservation, and continued use of burn ash pits for waste disposal is suspected. As a result of illegal dumping and burning, hazardous materials that were detected in harmful concentrations prior to the cleanup included lead arsenic, mercury, asbestos, barium, cadmium, chromium, copper, zinc, freon, and used oil, among others. It is not known to what degree these contaminants may have leached into the groundwater, although ongoing monitoring of the Tribe’s well water has shown no violations of US EPA primary drinking water standards.

The old Reservation is surrounded by agricultural land, primarily used for dairy and beef cattle. Since livestock wastes are a potential source of biological and inorganic contaminants their presence around the old Reservation, and in proximity to the wellhead, indicate a potential contamination issue for the Tribe’s ground water.

Additionally there are septic systems associated with the home sites at the old Reservation. Some are about 150 to 175 feet away from the wellhead. In 1991, sanitation issues including inadequacy of septic systems, high water table, and drinking water contamination of the Tribe’s well prompted drilling of a new well. Unfortunately, the present community well was drilled only 100’ distant from the old well, although at least 12’ deeper. While there are problems with high concentrations of iron, manganese, and chloride, water from the present well has had no violations for US EPA drinking-water regulated contaminants, thus far.

Old wells left unused or improperly abandoned are a hazard since the wells can be a direct conduit for contaminants to reach groundwater. Abandoned wells need to be sealed carefully to prevent pollution of the groundwater source, eliminate any physical hazard, conserve aquifer yield, and prevent poor quality water of one aquifer from entering another. It is not known at this time how many old residential wells on the old Reservation have been improperly abandoned.

View of old Reservation, during cleanup in May 2002; these vehicles and associated waste were all removed.

McNulty Slough passes nearby the old Reservation, and within 40 yards of the Tribe’s community wellhead.

Water pollution Control Program

Background Tribe's Water Resources The Old Reservation

Threats to the Old Reservation Table Bluff Reservation Treats to TBR Water

Indian Island Threats to Indian Island Water Water Monitoring

Indian Island Cultural & Environmental Project

Environmental Department | Social Services