62-528.425. Monitoring Requirements for Class I and III Wells

(1) Class I Wells. For Class I wells, monitoring requirements shall include:

(a) The analysis of the injected fluids at a frequency specified in the permit to yield representative data on their characteristics;

(b) The installation and use of continuous indicating, recording, and totalizing devices to monitor flow rate and volume, and installation and use of continuous indicating and recording devices to monitor the injection pressure and the pressure on the annulus between the tubing and the final or innermost string of casing, if there is an annulus;

(c) A controlled injection test or a bottom hole pressure survey, if a long-term trend of increasing injection pressure is indicated.

(d) A demonstration of mechanical integrity pursuant to subsection 62-528.300(6), F.A.C., at least once every five years during the life of the well; and

1. As part of the baseline monitoring information, a video television survey from the surface to the bottom of the injection zone shall be run prior to injection but after completion of testing, except for those wells that inject through tubing or where it is physically impossible to do so, and every five years thereafter, or more frequently if impairment of the integrity of the casing, tubing, or formation is suspected based on physical or geochemical data such as water quality, pressure changes, or mechanical integrity results.

2. The television survey may be either black and white or color.

3. Adequate provisions shall be made to centralize the camera in the borehole.

4. Before running the survey, adequate provisions shall be made to assure that fluid in both the casing and open borehole is of sufficient clarity to provide a baseline survey of a quality acceptable to the Department.

(e) An application to construct or operate a Class I well, and such permit shall address the following:

1. The type, number, and location of well(s) within the area of review to be used to monitor:

a. Any potential migration of fluids into or in the direction of underground sources of drinking water, and

b. Pressure in the underground sources of drinking water;

2. The parameters to be measured; and

3. The frequency of monitoring.

(f) The background water quality of the injection zone and the monitoring zone(s) shall be determined prior to injection for both domestic wastewater wells and industrial Class I wells (including desalination process reject water), in accordance with the sampling and testing methods outlined in Rule 62-601.400, F.A.C. Background levels shall be determined pursuant to the following criteria:

1. For monitor zones in Class G-I, F-I, G-II or G-III ground waters the primary and secondary drinking water quality parameters listed in Rules 62-550.310 and 62-550.320, F.A.C., and the minimum criteria provided in Rule 62-520.400, F.A.C.

2. For the injection zone and monitor zones in G-IV ground water the criteria shall be established in accordance with Rule 62-520.440, F.A.C.

(g) The Department shall require monitor wells above the injection zone near the injection well, field or project.

1. The permittee shall be able to monitor the following:

a. The absence of fluid movement adjacent to the well bore, and

b. The long-term effectiveness of the confining zone.

2. Monitor wells used to meet the requirements of subparagraph 1. above shall be sampled periodically. The frequency of sampling and constituents to be analyzed shall be specified in the permit and shall be representative of the monitored activity.

3. Monitor wells used to meet the requirements of 1.a. above shall be located within 150 feet of the injection well unless the applicant can demonstrate, through a hydrogeologic study, that a monitor well located at a greater distance will be capable of adequately monitoring fluid movement adjacent to the borehole.

4. The permittee shall monitor a zone below the base of the underground source of drinking water, if a zone is available, and at least one zone within, and near the base of, the underground source of drinking water.

5. The Department shall also require any of the following when needed to provide reasonable assurance that the requirements of 1. above are being met:

a. Continuous monitoring for pressure changes in the first aquifer overlying the confining zone.

b. Continuous monitoring for pressure changes in any monitor well constructed under subparagraph 1. above.

c. Periodic monitoring of ground water quality in the first aquifer overlying the injection zone.

d. Periodic monitoring of ground water quality in the lowermost underground source of drinking water.

e. Periodic additional monitoring to determine whether fluid movement caused by underground injection activity is occurring into or between underground sources of drinking water.

(h) The Department shall require monitor wells above and in the injection zone at a sufficient distance from the well, field or project for regional monitoring if such monitoring is necessary to protect waters of the State.

(i) When direct monitoring required under paragraph (g) above can not be provided or the results of such monitoring fail to provide reasonable assurance, the Department shall require the additional use of indirect geophysical techniques and computer modeling or such other techniques capable of providing reasonable assurance as to:

1. The position of the waste front,

2. The water quality in a formation or zone, or

3. Other site specific data.

(j) For Class I wells, a five gallon unacidized representative sample of native water from the injection zone shall where practical be collected and provided to the Florida Department of Environmental Protection, 2600 Blair Stone Road, Tallahassee, Florida 32399-2400 or a laboratory specified by the Department.

(k) Post-closure Monitoring. For Class I wells, if necessary to protect underground sources of drinking water the permit applicant shall be required to submit a post-closure monitoring plan designed to monitor the attenuation of any pressure effects and water quality changes caused by the underground injection operation both in the injection zone or in overlying aquifers. The proposed monitoring plan shall at a minimum use the injection wells and associated monitor wells, to the extent that they are capable of yielding representative ground water samples. The proposed monitoring plan may also include other accessible wells.

1. Items to be addressed by the permit applicant in the proposed post-closure monitoring plan shall include:

a. Designation of the wells to be used for post-closure monitoring;

b. The parameters to be monitored, by well;

c. The sampling frequency;

d. The proposed duration of the post-closure monitoring period; and

e. A documented estimate of the total cost of the post-closure monitoring program.

2. A revision of the post-closure monitoring plan shall be required by the Department when needed to reflect changes in the design or scope of the underground injection operation, inflation of costs associated with the plan, or other factors resulting from the construction or operation of the injection well system. The permittee also may initiate modification of the post-closure monitoring plan.

(2) Class III Wells. For Class III wells, monitoring requirements shall specify:

(a) The analyses of the physical and chemical characteristics of the injected fluid with sufficient frequency to yield representative data on its characteristics;

(b) Installation and use of continuous recording devices to monitor the injection pressure, flow rate and volume;

(c) The demonstration of mechanical integrity pursuant to subsection 62-528.300(6), F.A.C., at least once every five years during the life of the well;

(d) Weekly monitoring of fluid level and of the parameters chosen to measure water quality in the injection zone with sufficient frequency to yield representative data on its characteristics;

(e) Quarterly monitoring of wells adjacent to the injection site to detect any migration from the injection zone into an underground source of drinking water;

(f) All Class III wells may be monitored on a field or project basis rather than an individual well basis by manifold monitoring. Manifold monitoring may be used in cases of facilities consisting of more than one injection well operating with a common manifold. Separate monitoring systems for each well are not required provided the permittee demonstrates that manifold monitoring is comparable to individual well monitoring;

(g) The applicant shall continue monitoring after mining operations cease if site-specific factors or operational monitoring results indicate that there is a threat to an underground source of drinking water. Such monitoring shall continue until no threat remains. If the monitoring reveals violations, the permittee shall investigate and take corrective action.

(h) Monitoring Criteria.

1. Where injection is into a formation which contains water with less than 10,000 mg/L total dissolved solids, monitoring wells shall be completed into the injection zone and into any underground sources of drinking water which could be affected by the mining operation. These wells shall be located as to detect any excursion of injected fluids, process by-products, or formation fluids outside the mining area or zone. If the operation may be affected by subsidence or catastrophic collapse, the monitoring wells shall be located so that they will not be physically affected.

2. Where injection is into a formation which does not contain water with less than 10,000 mg/L total dissolved solids, monitoring wells shall be required above and in the injection zone if necessary to protect underground sources of drinking water.

3. Where the injection wells penetrate an underground source of drinking water in an area subject to subsidence or catastrophic collapse an adequate number of monitoring wells shall be completed into the underground source of drinking water to detect any movement of injected fluids, process by-products or formation fluids into the underground source of drinking water. The monitoring wells shall be located outside the physical influence of the subsidence or catastrophic collapse.

4. The Department shall require monitoring for subsidence if necessary to protect property or underground sources of drinking water.

(i) In determining the number, location, construction and frequency of monitoring of the monitoring wells, the following criteria shall be used:

1. The population relying on the underground source of drinking water affected or potentially affected by the injection operation;

2. The proximity of the injection operation to points of withdrawal of drinking water;

3. The local geology and hydrology;

4. The operating pressures and whether a negative pressure gradient is being maintained;

5. The toxicity and volume of the injected fluid, the formation water, and the process by-products; and

6. Number of injection wells per unit area.

Specific Authority 403.061, 403.087 FS. Law Implemented 403.021, 403.061, 403.062, 403.087, 403.161 FS. History–New 4-1-82, Amended 5-8-85, Formerly 17-28.25, 17-28.250, 62-28.250, Amended 8-10-95, 6-24-97.