142 REPORT OF INVESTIGATIONS NO. 50
Owners, managers, and caretakers in charge of a total of about 39,000 acres of citrus trees in Orange County (62 per cent of the acreage in the county) were asked about their irrigation practices. They reported that about 14,000 acres (36 percent of the acres inventoried) were irrigated in 1963 with an average of about 6 inches of water per year. About 45 percent of the water used came from wells, the remainder coming from lakes. Assuming that irrigation practices on the 24,000 acres of citrus groves not inventoried are similar to the practices on the 39,000 acres inventoried, water use in citrus irrigation in Orange County in 1963 averaged about 10 mgd or about 11,000 acre feet per year.
An estimated 1 mgd of ground water was used in 1963 to irrigate approximately 1,500 acres of pasture in Orange County.
SURFACE WATER
Use of surface water for irrigation of citrus groves in Orange County was reported to have averaged about 5.5 mgd in 1963. An additional amount was used from Lake Apopka to irrigate about 6,000 acres of row crops in the Zellwood muckland truck farming area. No accurate figures are available on the amount of water used because the water enters by gravity flow through a number of individually-controlled pipes in the levee that separates the farming lands from Lake Apopka. A rough estimate of water use in the Zellwood area, based on normal water use of plants, is between 5 and 10 mgd. However, Mr. Hodges, manager of the Zellwood Drainage and Water Control District, reported (oral communication, October 1962) that, on the average, more water was pumped from the District into Lake Apopka than flowed into the District from the lake. This is probably because of seepage of ground water into the District from the surrounding sand hills and Lake Apopka and the absence of downward leakage of rain water within the District, because the piezometric surface is near or above the land surface.
An average of about 110 mgd of surface water is used in cooling the electric generators in the Orlando Utilities power plant in Orlando. This water is pumped from Lake Highlands and discharged into Lake Concord from which it flows into Lake Ivanhoe and then back into Lake Highland. Because of this circulation, little of the cooling water is consumed, and the only effect is a slight rise in the water temperature of the lakes involved. The Orlando plant was put on stand-by status in 1964 and is only used during peakload times and during emergencies.