Section 506.206  Groundwater Monitoring

a)         The owner or operator of any livestock waste lagoon required to implement groundwater monitoring under Section 506.204(d) must implement a monitoring program that complies with this Section and 8 Ill. Adm. Code 900.Subpart F.

b)         The groundwater monitoring network must consist of at least three monitoring wells located within 20 feet of the exterior toe of the berm. At least two of the required wells must be located downgradient of the lagoon based on local groundwater conditions.  The groundwater monitoring network design must consider multiple cell lagoons as a single lagoon.

c)         The monitoring wells must be installed in compliance with the following:

1)         The requirements of the Illinois Water Well Construction Code at 77 Ill. Adm. Code 920.170;

2)         The top of the well screen must be set at the estimated seasonal low water table elevation;

3)         Monitoring wells must use a minimum of a five-foot screened interval; and

4)         The screen must be set in a sand pack that extends at least one foot above and one foot below the screened interval.

d)         The owner or operator must sample the wells, analyze the samples, and report the results in compliance with 8 Ill. Adm. Code 900.Subpart F.

e)         The owner or operator of the earthen livestock lagoon may, upon written request and with written approval from the department, modify or exceed these standards in order to meet site specific objectives. [510 ILCS 77/15(a)] The owner or operator must demonstrate that such modification must be at least as protective of the groundwater, the surface water, and the structural integrity of the livestock waste management facility in compliance with this Part.

(Source:  Amended at 48 Ill. Reg. 3274, effective February 15, 2024)