Clermont Chain of Lakes
As of this afternoon, Lake Minnehaha is at 96.94 ft. which is slightly more than 6 inches below the upper end of the regulatory range of 97.50. The area received significant rain the week of August 21st and the lake level began rising quickly. Water Authority staff made a decision to open the Cherry Lake Dam slightly to make sure everything was going to work and to watch how the system would respond, particularly after the completion of the fixed crest weirs at M-5 and M-6. Hurricane Irma started becoming more of a threat over the Labor Day weekend and on Tuesday, Sept 5th, staff opened the Cherry Lake Dam all the way allowing approximately 1,000 cfs to start moving through the system. As the pools downstream started to fill, the discharge rate from Cherry Lake starts to slow down. As of this afternoon, we are still moving 632 cfs through the Cherry Lake Dam. Flow from Big and Little Creeks have remained fairly steady over the past week with Big Creek discharging at 30.7 cfs and Little Creek discharging at 37.0 cfs for a combined flow of 67.7 cfs. At the current flow rate from the Cherry Lake Dam (nearly 10 times the flow coming in) we should be able to gain another 3-4 inches of storage before the effects of Hurricane Irma are felt in Central Florida.
Harris Chain of Lakes
Lake Apopka area received significant rainfall during the end of August that moved lake levels above the regulatory schedule. On Tuesday, August 29th the St. Johns River Water Management District (SJRWMD) started releasing about 25 cfs through the NuRF. The rains continued and on Friday morning, September 1st the SJRWMD increased flow to 100 cfs with the likelihood of greater flows over the holiday weekend. Due to directions from Tallahassee to aggressively prepare for Hurricane Irma to ensure there would not be Houston-like flooding issues in Florida, SJRWMD increased flow from Lake Apopka to 350 cfs, the maximum design capacity of the Water Authority’s Nutrient Reduction Facility (NuRF – the off-line alum treatment facility on the Apopka Beauclair Canal), on Friday afternoon, September 1st.
The SJRWMD staff received further direction to increase their efforts to ensure the Harris Chain of Lakes is prepared for any rain that may come with the hurricane. As such, the SJRWMD opened the Apopka Dam on Tuesday, September 5th to allow an additional 100 cfs (in addition to what is passing through the NuRF) out of Lake Apopka. Because of the immediate fast flow, the canal upstream of NuRF (closer to Lake Apopka) picked up a significant amount of sediment and vegetation causing the water to become very turbid. This caused the oxygen to become depleted, particularly overnight and in the early morning hours, to the point where a fish kill occurred due to no dissolved oxygen. Currently there is 75 cfs moving through the Apopka Dam and the SJRWMD has alerted us today that they will likely close the dam soon and direct all flow back through the NuRF.
The SJRMWD is also making releases from the other lakes as well. They are currently releasing 854 cfs through the Burrell structure that controls Lakes Beauclair, Dora, Eustis and Harris into Lake Griffin. In addition, the Harris Bayou structure has been opened allowing 50 cfs to be discharged from Lake Harris directly to Lake Griffin. Lake Griffin is still nearly a half a foot below the regulatory schedule but is quickly rising and the Moss Bluff structure may be opened later in the week.
Please make sure you are all prepared for the storm and its aftermath.