AGENDA ITEM. RECOMMENDATION: Receive Status Report.

Transcription

1 AGENDA ITEM C2 DATE: June 3, 13 TO: Charles H. Carden, Interim General Manager FROM: Christine Owen, Senior Manager Regulatory Compliance SUBJECT: Production Update and Hydrologic Conditions Report for April 13 and May 13 and the past 12-Month Period (June 1, 12 through May 31, 13) - Status Report SUMMARY: The following report summarizes water production and hydrologic conditions in the three-county Tampa Bay area (Tri-county area) during April 13 and May 13 and the past 12-Month Period (June 1, 12 through May 31, 13). RECOMMENDATION: Receive Status Report. I. Rainfall/Climate Tampa Bay Water monitors daily rainfall at numerous sites on and near our water supply facilities. The data discussed in this report are collected at seven of Tampa Bay Water s regional wellfields and at the Tampa Bypass Canal. These data are compared to historical rainfall data to help assess the current hydrologic conditions near our wellfields and surface water sources. These data assessments help guide the Agency s supply management decisions and enhance our ability to coordinate and communicate with our Member Governments and regulators. The rainfall data are summarized below and presented geographically in Figures 1 through 3. Tri-county rainfall during April 13 ranged from 1.9 to 5. inches and averaged 1.3 inches above the historical average for the month, based on wellfield sites. Tri-county rainfall during May 13 ranged from 2. to 4.9 inches and averaged.5 inch below the historical average for the month, based on wellfield sites. Tri-county rainfall based on wellfield sites during the 12-month period ending May 31, 13, ranged from 5.3 to 62.6 inches depending on location, and averaged 3.7 inches above the historical 12-month average. II. Regional Water Resource Production Water production data from Tampa Bay Water s permitted resources for April 13 and May 13 are summarized below and provided in additional detail in Table 1 and Figures 4 and 5. Agenda Item F-3 included in this Board Agenda Packet contains further information regarding supply conditions. t:\board folders\board agenda\approved items\c2 hydrologic conditions.doc

2 Charles H. Carden June 3, 13 Page 2 The Consolidated Permit (11 wellfields) 12-month running average production for the period ending May 31, 13, was million gallons per day (mgd) compared to the 9 mgd permit limit. The South-Central Hillsborough Wellfield 12-month running average production for the period ending May 31, 13, was 19.9 mgd compared to the 24.1 mgd permit limit. The average Tampa Bay Water source water distribution for the past 12 calendar months was: Groundwater 6.2 mgd (65.5% of total); Surface Water. mgd (27.8% of total); and Seawater Desalination.9 mgd (6.7% of total). III. Environmental Conditions Tampa Bay Water closely monitors the environmental conditions around Agency wellfields and these data are used to guide production and wellfield management decisions. Figure 6 depicts the locations of selected Upper Floridan Aquifer monitor sites and lake or wetland sites. A summary of observed conditions in and around the 11 Consolidated Permit Wellfields is provided in Figures 7 through 16. These figures show pumpage and rainfall at wellfields for the past fifteen years as well as water-level data from the Upper Floridan Aquifer and a lake or wetland located on or near that wellfield. A reference line on the lake and wetland hydrographs shows the lake minimum level or the normal pool elevation in the wetland. The normal pool elevation of a wetland is the water-surface elevation that is normally reached at the end of the rainy season during an average rainfall year. This is typically the highest water level reached in a wetland during an average rainfall year; water levels are expected to fluctuate below this elevation during the year. Water levels in lakes and wetlands respond more directly to changes in rainfall than does the Floridan Aquifer. Many lakes and wetlands recovered to normal or above-normal levels during 12 due to high rainfall totals during the summer months. These high water levels have gradually declined to normal seasonal levels by the end of the current spring dry season. Even with substantially reduced groundwater production, because of the strong relation to rainfall conditions, water levels in some lakes and wetlands on and near wellfields will exhibit normal water level fluctuations only as rainfall occurs in normal or above-normal amounts. With a sustained reduction in groundwater pumpage and normal rainfall, water levels in area lakes and wetlands should more closely approximate normal water-level fluctuations. t:\board folders\board agenda\approved items\c2 hydrologic conditions.doc

3 Charles H. Carden June 3, 13 Page 3 General water-level changes are summarized as follows: Groundwater levels generally decreased about.5 foot during April 13. Groundwater levels generally decreased about.6 foot during May 13. Groundwater levels in May 13 were generally 2.8 feet higher than in May 12. Average water levels in the indicator lakes and wetlands located on and near Consolidated Permit Wellfields decreased 7.6 inches during April 13, and decreased 4.1 inches during May 13 (based on data collected throughout the month, not necessarily end-of-month). Average water levels in the indicator lakes and wetlands in May 13 were about 15.8 inches higher than water levels in May 12. IV. Enhanced Surface Water System Tampa Bay Water s Enhanced Surface Water System is comprised of surface water withdrawals from the Alafia River, Hillsborough River and Tampa Bypass Canal, and the C.W. Bill Young Regional Reservoir. Current hydrologic conditions in the three Tampa Bay Water surface water sources and the Regional Reservoir are summarized below. Figures 17 and 18 illustrate surface water conditions in the two river sources. Figure 19 shows the monthly storage and withdrawal volumes and cumulative storage volume of the C.W. Bill Young Regional Reservoir. The Regional Reservoir was taken off line at the end of December 12 in preparation for the renovation project. Flow in the Alafia River at Bell Shoals was 52% below normal in April 13, and 14% below normal in May 13. Flow in the Hillsborough River was 63% below normal in April 13, and 31% below normal in May 13. Information regarding withdrawals from the Tampa Bypass Canal is included Agenda Item F-3 in this Board Agenda Packet. Attachments t:\board folders\board agenda\approved items\c2 hydrologic conditions.doc

4 TABLE 1 Regional Production Table Month Consolidated Permit Wellfields Monthly Production (mgd) *Surface Water Monthly Production (mgd) Seawater Desalination Plant Monthly Production (mgd) **Other Groundwater Facility Monthly Production (mgd) April (WY12) May June July August September October (WY13) November December January February March April May Month Average Difference Between May 12 and May * Tampa Bay Water Surface Water Treatment Plant and the Tampa-Hillsborough Interconnect (THIC) **South Central Hillsborough Regional Wellfield, Brandon Wells, Carrollwood Wells, and the Eagles Wells

5 April 13 Rainfall Figure (+.1) 2.4 (+.6) 3. (+1.6) 2.8 (+.8) 5. (+3.) 2.6 (+.6) 3.6 (+2.1) 3.2 (+1.7) 3.2 Example of Actual Monthly Rainfall (+1.7) - Variance From Normal (NOAA)

6 May 13 Rainfall Figure ( 2.4) 4.9 (+.2) 2. ( 1.4) 3.9 (+.3) 3.5 (.1) 3. (.6) 3.8 (+.1) 3.8 (+.1) 3.8 Example of Actual Monthly Rainfall (+.1) - Variance From Normal (NOAA)

7 Cumulative Rainfall For The Past 12 Months (June 1, 12 Through May 31, 13) Figure (+1.3) 58. (+3.9) 53.6 (+2.6) 6.6 (+6.8) 5.3 ( 3.5) 55.5 (+1.7) 62.6 (+11.9) 55.4 (+4.7) 55.4 Example of Actual Annual Rainfall (+4.7) - Variance From Normal (NOAA)

8 12 Month Running Average and Monthly Production - Consolidated WUP Wellfields Figure 4

9 South Central Hillsborough Service Area Demand and Supply 36 (12 month running average = 19.9 mgd as of 5/31/13) Compliance Level for SCH Wellfield (24.1 MGD) SCH Wellfield Production (MGD) Monthly Production SCH Wellfield Month Running Average from SCH Wellfield Figure 5 BUDW Production WY through WY 13 (To Date) BUDW Production (MGD) 34

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11 Eldridge Wilde Wellfield Figure 7 Floridan Aquifer Levels Well 2N (Site 11) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date 2N Annual Refernce Point Water Year Wellfield Production (mgd) Wetland Water Levels ELW NW (Site 9) 4 33 Monthly Average Production (mgd) Normal Pool NW Normal Pool Annual Reference Point

12 Section 21 Wellfield Figure 8 5 Floridan Aquifer Levels Well J26 Ad (Site 12) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date J26 Ad Annual Reference Point Water Year 14 Wellfield Production (mgd) 55 Lake Water Levels Starvation Lake (Site 13) Proposed MinimumLevel Monthly Average Production (mgd) Starvation Lake Pr oposed Minimum Level Annual Reference Point

13 Cosme Odessa Wellfield Figure 9 4 Floridan Aquifer Levels Well Cosme 3 (Site 15) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date 15 Cosme 3 Annual Reference Point Water Year Wellfield Production (mgd) 55 Wetland Water Levels COS SE (Site 16) Normal Pool Monthly Average Production (mgd) SE Normal Pool Annual Reference Point

14 Starkey/North Pasco Wellfields Figure Floridan Aquifer Levels Well PZ 4D (Site 6) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date 15 PZ 4D Annual Reference Point Water Year Wellfield Production (mgd) Wetland Water Levels STKY S 95 (Site 3) Monthly Average Production (mgd) Normal Pool S 95 Normal Pool Annual Reference Point

15 South Pasco Wellfield Figure 11 6 Floridan Aquifer Levels Well SR 54D (Site 7) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date 3 SR 54D Annual Reference Point Water Year Wellfield Production (mgd) 65 Wetland Water Levels SOP PT (Site ) Monthly Average Production (mgd) Normal Pool PT Normal Pool Annual Reference Point

16 Northwest Hillsborough Regional Wellfield Figure 12 5 Floridan Aquifer Levels Well RMP 18D (Site 17) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date RMP 18D Annual Reference Point Water Year 16 Wellfield Production (mgd) Wetland Water Levels NWH (Site ) Monthly Average Production (mgd) Normal Pool 2 2 Site Normal Pool Annual Reference Point

17 Morris Bridge Wellfield Figure 13 Floridan Aquifer Levels Well MBR 6D (Site 19) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date MBR 6D Annual Reference Point Water Year 3 Wellfield Production (mgd) 4 Wetland Water Levels MBR 16 (Site 18) Normal Pool Monthly Average Production (mgd) MBR 16 Normal Pool Annual Reference Point

18 Cypress Creek Wellfield Figure 14 7 Floridan Aquifer Levels Well TMR 4D (Site 4) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date 4 TMR 4D Annual Reference Point Water Year Wellfield Production (mgd) Wetland Water Levels CYC W 56 (Site 5) Monthly Average Production (mgd) Normal Pool Site W 56 Normal Pool Annual Reference Point

19 Cypress Bridge Wellfield Figure 15 Floridan Aquifer Levels Well FL 5 5 (Site 8) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date 4 FL 5 5 Annual Reference Point Water Year Wellfield Production (mgd) Wetland Water Levels CYB #32 (Site 14) Normal Pool Monthly Average Production (mgd) CYB #32 Normal Pool Annual Reference

20 Cross Bar Ranch Wellfield Figure 16 5 Floridan Aquifer Levels Well NRW D (Site 1) Rainfall Yearly Total Rainfall (inches) Total WY13 Rainfall to Date NRW D Annual Reference Point Water Year Wellfield Production (mgd) Wetland Water Levels CBR T 3 (Site 2) Normal Pool 71 Monthly Average Production (mgd) T 3 Normal Pool Annual Reference Point

21 Regional Surface Water Discharge April 13 Figure 17 Hillsborough at Morris Bridge (1) Estimated Flow, Alafia at Bell Shoals (2) 1 Estimated Flow, Alafia at Bell Shoals (2) 2

22 Regional Surface Water Discharge May 13 Figure 18 Hillsborough at Morris Bridge (1) 1 Estimated Flow, Alafia at Bell Shoals (2) 2

23 Reservoir Monthly Storage, Withdrawal, and Cumulative Storage Volume Figure Month Storage Volume (Billions of Gallons) Monthly Diversions (Billions of Gallons) 8