About Montecito Lakes
Lake Sizes & Engineering
These lakes are estimated to have 6,344 linear feet of shoreline area and a total size of 9.03 acres. The shoreline length and total area of the lakes are shown below:
|Lake||Shoreline||Total Area (Acres)|
- normal water level = +4.10 ft NGVD
- seasonal low water level = +3.20 ft NGVD (well pump turn off elevation) / (well pump turn on elevation = +3.03 ft NGVD
- measured lake level on Feb 4, 2019 = +3.81 ft NGVD
|Sample Date||Lake Catalina Measured Level (NGVD)|
All of the lakes should be at the same height level. During the creation of the lakes, underground equalizer pipes were placed which interconnect them. The purpose of the equalizer pipes is to keep the water in the lakes at the same level.
Water enters the lakes in two ways:
- Rainwater, including rainwater runoff (via the storm sewers on the streets) and
- By two underground artesian wells, one emptying into lake number 2 (Well #1) and one emptying into lake number 3 (Well #2).
Water leaves the lakes by evaporation and by pumping for irrigation. Irrigation pumps are located on lake 2, lake 3 and lake 5. Typical irrigation requires the pumping out in excess of 400 gallons per minute.
When the lakes were created, it was anticipated that rainfall would be the primary source of water to maintain adequate levels.
The volume of water which enters the lakes from the wells is regulated by the Saint Johns River Water Management District and limits on it are specified in the consumptive use permit (CUP) that is issued by this government agency. The initial CUP was issued on 10 May 2006 and was transferred to Montecito CDD on 21 October 2009.
With the exception of a prolonged drought, the permit limits the addition of well water to the lakes (from all sources combined) to a volume of 30 gallons per minute. Importantly, the CUP mandates regular monitoring and reporting of both the levels and chemical composition of the water in the lakes. Notably, the volume of water that can be added to the lakes from the wells is small and alone would not be expected to keep the water levels adequately high to serve our irrigation needs on an ongoing basis.
Monitoring Water Quality for Irrigation Purposes
The water in our lakes is brackish. That is, it contains some salt (sodium chloride). As such, it cannot be used for drinking but, as long as the sodium chloride concentration is not too high (<1,100 mg/L), it can be used to irrigate our lawns and flora. If the salt concentration in the lake water exceeds 1,100 mg/L, it may damage and/or kill the grass and other vegetation if used for irrigation.
TDS is a measure of total dissolved solids, not just salts (chlorides). Other common constituents include sodium, potassium, calcium, magnesium, sulfate, etal. that are included as a part of the TDS measurement. The total dissolved chlorides in a TDS measurement for Floridan Aquifer System water is normally between 50% and 60% of the TDS value. It might be slightly less for lake/surface waters depending on there proximity to salt/brackish surface water.
At the first of each month, our Onsite District Facilities Supervisor takes TDS (Total Dissolved Solids) Measurements. Separate measurements are captured:
- at each lake
- at each artesian well
- First, we must receive adequate rainfall to maintain adequate water levels in our lakes.
- Second, the sodium chloride concentration of our lakes, is very close to making the water unusable for irrigation without the risk of damaging or killing the vegetation.
- Third, we cannot just increase the well water inflow to compensate for the lack of natural precipitation that we may experience due of the high sodium chloride concentration in the well water.
- Fourth, there will be challenges obtaining adequate water to irrigate the additional common areas and private lawns being created in the phase 2C townhomes development, which is ongoing presently.
Lake TDS Measurements
Total Dissolved Solids (TDS) in CDD lake water are measured on a monthly basis. The table below lists results found. Values are color coded to indicate:
- Green - Values less than 1,000 mg/L - Safe to use for irrigation
- Yellow - Values between 1,001 and 1,299 mg/L - Potentially harmful and should be limited use for irrigation
- Red - Values greater than 1,300 mg/L - Water is NOT Safe to use for irrigation
|Sample Date||LakePasadenaTDS (mg/L)||LakeValenciaTDS (mg/L)||LakeSonomaTDS (mg/L)||LakeCatalinaTDS (mg/L)||LakePacificaTDS (mg/L)||LakeCoquinaTDS (mg/L)|
Artesian Well TDS Measurements
Total Dissolved Solids (TDS) in CDD underground artesian wells are measured on a monthly basis. The table below lists results found:
|Sample Date||Well 1 TDS (mg/L)||Well 2 TDS (mg/L)|