ATTACHMENT 4 TURBIDITY MONITORING PLAN

Transcription

1 ATTACHMENT 4 TURBIDITY MONITORING PLAN

2 Turbidity Monitoring Plan The construction of this project will require in-water soil disturbing activities, which must meet the state s water quality antidegradation criteria. The state allows a mixing zone to be established in which the turbidity disturbed waters must meet state water quality standards at the mixing zone boundary. Lake Panasoffkee is considered an Outstanding Florida Water (OFW). The contractor shall meet the following conditions: 1. Existing ambient water quality within the mixing zone may be degraded to allow for inwater construction activities. Turbidity levels shall not average greater than forty-one (41) Nephelometric Turbidity Units (NTUs) above natural background conditions at the mixing zone boundary [F.A.C (1)(j)]. 2. Ambient background samples shall be collected at the edge of ROW up stream from the source of turbidity. The background sampling sites will be marked by stakes or temporary buoys and shall be maintained for the duration of the sampling program. Background samples will be collected from the up-current sampling location at the surface, mid-depth and one foot above bottom. In water which is less than six feet deep, mid-depth samples are not required. 3. All construction activities that have a potential to create turbidity, such as box culvert extensions that require in-water soil disturbance, dredging and filling, and any bridge demolition shall require monitoring. Sampling shall commence prior to the start of construction activities, and continue twice daily, with a maximum of four-hour intervals, during ongoing potential turbidity creating construction activities. Samples shall be collected at the mixing zone boundary. The mixing zone boundary shall extend to the edge of ROW downstream from the source of turbidity The contractor is encouraged to reduce the mixing zone below this threshold to minimize the impacts to the waterbody. 4. Samples will be collected from surface, mid-depth and one foot above bottom. In water which is less than six feet deep, mid-depth samples are not required. Sampling shall be conducted directly down current of the axis of the visible plume. If no plume is visible, samples will be collected at the intersection of the mixing zone boundary and a line parallel with the water current and extending from the source of turbidity. 5. All samples will be collected with a grab sampler which is designated to collect in situ water samples. Samples must be analyzed for turbidity as they are collected. The following information must be recorded for each sample taken and submitted in a Monitoring Report: a. Site number; b. Collector s name and affiliation c. Date and time of day when sample was collected; d. Sample collection depth and total depth; e. Antecedent weather conditions, including wind direction and velocity; and, f. Tidal stage and/or flow direction, if applicable. 6. In addition to the above mentioned, each Monitoring Report must include the following: a. A statement of methodology including types of sampling equipment and b. analytical instrumentation, preservation, and handling; c. Permit number; d. A map indicating numbered locations of all sampling sites;

3 7. All turbidity monitoring reports shall be submitted to the SWFWMD Brooksville office, attention Environmental Section within fourteen (14) days of sample collection. All correspondence should include the Permittee name and permit number. Failure to submit reports in a timely manner constitutes a violation of the permit and may be grounds for revocation. 8. The Permittee shall comply with the following QA/QC requirements for each sample collected: a. All turbidity analysis shall be performed on instruments that can perform Nephelometric measurements; b. The instrument must be calibrated each morning and each time the instrument is turned on, and recalibrated every four hours thereafter; c. Calibrations must be performed against a blank, and at least one formalin or geltype standard. The standard value should be in the same range as the sample readings. d. All calibration procedures must be recorded in a permanent log book, and copies must be submitted with the data; and, e. Date and time of collection, date and time of analyses, and the name of the analyst must be included in the log. 9. All in-water soil disturbing construction activities shall cease immediately whenever water quality samples exceed thresholds specified in item #1 at the boundary of the mixing zone. The violation shall be reported to SWFWMD at (352) within 4 hours of the violation. The violation report shall include the description of the corrective actions being taken or proposed to be taken. If violations are noted after normal business hours, on holidays or on weekends, the report shall be made to SWFWMD as soon as possible after normal business hours resume. A copy of all monitoring data sheets, which indicate violations, shall be forwarded immediately to the SWFWMD. 10. When a turbidity violation is found, in-water soil disturbing construction operations may not resume until a compliance inspection by District personnel has been conducted and a set of samples has been taken which demonstrate that the water quality standards designated above are being achieved. 11. Interim samples taken following the violation shall be taken in the same manner as the routine monitoring and at the same locations. If samples demonstrate the water quality standards specified for turbidity specified above are still being violated, sampling shall continue at two hour intervals until the interim samples demonstrate that water quality standards are being achieved. 12. Failure to report violations and stop work and submit a corrective action plan to SWFWMD for approval before resuming work will constitute grounds for enforcement action and may subject the Contractor to potential penalties enforced by FDOT and/or SWFWMD.

4 SAMPLING STATION #3

5 ATTACHMENT 1 UPDATED DEWATERING EXHIBITS

6 Existing Twin Culvert SAWCUT AND DEMO OPENING IN SIDEWALL OF EXIST. BOX Sheetpile Phase 2 for RI Additional Berm with Temp. Pipe to divert water. Berm to be used for additional access. Water Diverted Wing Walls Phase 1 for RI Sheet Pile Existing Berm Ramped area for Howard Baker equipment. Water Pump Sediment Basin