Monthly Assessment of Water Level Conditions in South Florida - Last Updated January 8, 2004

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Current Water Level Conditions

Southwestern Florida Ground Water

Southeastern Florida Ground Water

Surface Water

Background

Because rainfall has generally been normal, water levels in the majority of the ground-water monitoring wells in southern Florida are normal (Figure 4). Areas where the water levels are significantly lower than normal (such as portions of the mid Hawthorn and sandstone aquifers) are generally those same areas where water levels have declined over the long term as a result of extensive withdrawal for water supply. For example water levels in wells L-581 and L-2644 in the mid-Hawthorn Aquifer remain below the period-of-record extreme minimum for this week of the year (Figure 5) and (Figure 6) as a result of a long-term trend toward decreased water levels. However there are several locations where lower than normal water levels are occurring that are not directly related to long-term trends. These locations are, southeastern Miami-Dade, eastern Broward, Martin, and St. Lucie Counties.

Water levels at almost all of the surface-water monitoring sites are normal for this time of the year. Monitoring at the Caloosahatchee Canal has been discontinued by the USGS.

Current water conditions at selected stations are portrayed by a prototype web page that automatically performs statistical analysis of water-level data (Figure 4). Historical mean daily water levels and maximum daily water levels are analyzed respectively for surface water and ground water monitoring stations and comparisons between current and historical water-level data are presented. Water-level data is transmitted by satellite to the U.S. Geological Survey Miami Subdistrict Office every four hours. The statistical comparisons are being updated every four hours on the Florida USGS web site.

Southwestern Florida Ground Water

Shallow Aquifers:

Water Table Aquifer

Water levels in 4 (C-492, C-981, L-1995, and L-2195) of the 6 real-time monitoring wells that have sufficient daily-value data for analysis, indicate water levels that are normal for this time of the year. Water levels in monitoring well HE-862 are well above normal and near the period of record extreme for this week of the year this may be related to construction activities in the vicinity of the well. Water levels at monitoring well C-953 are slightly higher than normal. Data from October and November 2003 in well C-953 was bad because of a malfunction in the pressure transducer. This data will be corrected or deleted.

Lower Tamiami Aquifer

Water levels in 5 (C-462, C-951, L-738, L-2194 and L-5747) of the 6 real-time monitoring wells that have sufficient daily-value data for analysis, are normal. Water levels in well C-1004R (used in conjunction with data from C-1004) are slightly higher than normal.

Intermediate Aquifers:

Sandstone

Water levels in 5 (HE-556, L-729, L-731, L-1998, L-1994, and L-2186)of the 8 real-time monitoring wells in this aquifer are below normal relative to the long-term daily-value data. Water levels at wells L-731 and C-1079 are normal. Water levels at L-2215 are slightly above normal. However many of these wells have a long-term trend toward decreased water levels as a result of extensive withdrawal for water supply. After these trends have been considered and compensated for, water levels at all of the wells are at the levels that would be expected for this time of the year or higher.

Mid-Hawthorn

Despite relatively normal rainfall that occurred in November and December, water levels in all 4 of the wells that have sufficient data for analyses (L-581 (Figure 5), L-742, L-1993, and L-2644 (Figure 6)) are much lower than normal relative to the historical daily data. This is because all 4 of these wells indicate long-term, declining, water-level trends as a result of extensive withdrawal for water supply. After the data are adjusted for the long term trends, water levels at well L-1993 are above the levels expected for this week of the year, while water levels in wells L-581 and L-2644 are below even this level. This is because not only are water levels declining at wells L-581 and L-2644, but the rate of decline is increasing in L-2644 and possibly in L-581 as well.

Southeastern Florida Ground Water

Miami-Dade and Broward Counties (Biscayne Aquifer):Water levels in the majority of real-time monitoring wells in the Biscayne aquifer are near normal. Exceptions are the wells near the L-31 canal and West Well Field, wells G-1183 and G-3356 in southeastern Miami-Dade county, wells G-852 and G-970 in northern Dade County, and well G-1221 in southern Broward County, where water levels are slightly lower than normal. Conversely water levels are slightly higher than normal at wells G-2147 in northeastern Broward, wells G-789, and G-3622, S-196A in central Miami Dade County and G-620 in the Everglades.

Martin, Palm Beach and St. Lucie Counties (Surficial Aquifer System):Water levels at four ( M-1004, M-1048, M-1261 and STL-125) of the seven real-time monitoring wells in the surficial aquifer system are below normal for this time of the year relative to historical water level data. Water levels at the remaining thee wells (PB-565, PB-689, and PB-1491) are normal for this week of the year. There are statistically significant long-term downward trends in water levels in wells M-1261 and PB-689. Therefore below normal water levels are not unusual in either well. Once the long term trends have been compensated for, current water levels are as expected at M-1261 and slightly higher than expected at PB-689.

Surface Water

Water levels in all of the monitoring stations in the Water Conservation Areas are normal for this week of the year.

Water levels in the Imperial River and Spring Creek in Lee County are normal for this week of the year. Water levels at Gator Slough, which is also in Lee County are slightly below normal.

Water levels in Lake Okeechobee at the North New River near structures S-2 and S-351 are about normal. Monitoring by the USGS has been discontinued at the Caloosahatchee Canal and this station will soon be removed from the statistical analysis website.

Background

The U.S. Geological Survey operates ground-water and surface-water monitoring stations as a cooperative effort with other Federal, State, county and municipal agencies or departments. Five-hundred and eight stations are used to monitor ground-water levels and chloride concentrations in the major aquifers of south Florida. One-hundred and forty four surface-water monitoring stations are used to evaluate stage, discharge, and water quality. Unusually dry conditions in south Florida this spring led to decreased water levels in many of south Florida's aquifers. Of the 508 ground-water monitoring stations about 498 are used to monitor water levels or a combination of water levels and chloride concentrations.

Figure 1. Precipitation from November 2, 2003, to January 5, 2004, from South Florida Water Management District.

Figure 2. Precipitation from January 2, to January 5, 2004, from South Florida Water Management District.

Figure 3. Precipitation from December 31, 2003, to January 7, 2004, from WSI Corporation, Intellicast Weather.

Figure 4. Statistical Overview of Select USGS Water-level Monitoring Sites, January 7, 2004.

Figure 5. Current 90-day hydrograph at L-581 (263532081592201).

Figure 6. Current 90-day hydrograph at L-2644 (263440082022001).