Presentation on theme: "Sun Ag Water Quality Study Report for Total Phosphorus Marc von Canal, Regulatory Scientist Mark Crosby, Engineer Victor McDaniel, Supervising Professional."— Presentation transcript:
Sun Ag Water Quality Study Report for Total Phosphorus Marc von Canal, Regulatory Scientist Mark Crosby, Engineer Victor McDaniel, Supervising Professional Engineer SJRWMD, Division of Surface Water Management June 6, 2000
Purpose and Goals of Study Locate sources of high concentration of Total Phosphorus (TP) Identify contributing factors to these high concentrations of TP Investigate correlation between high on-site TP and high TP discharged at pump stations Use information to make recommendations regarding more effective on-site management practices to help reduce TP discharge loads
Background 26,000-acre farm in Indian River County Bordered by Fellsmere Canal & C-54 to North Berry Groves and City of Fellsmere to East BCWMA to South SJWMA and Blue Cypress Marsh CA to West (Illustrated on following map)
Sun Ag Local Area Map
Sun Ag Land Use Land uses include Citrus, Pasture, Sod and Row Crops
Sun Ag Irrigation & Drainage Western area primarily seepage irrigated by surface water from SJWMA Eastern area primarily microspray irrigated by groundwater Drainage is by 7 pump stations
BCWMA-W BCWMA-E Fellsmere Canal SJWMA C-54 Blue Cypress Lake BCMCA S-96D S-96 S-96C S-96B BCMCA Plug S-254 Berry Groves
Study Design Delineated farm according to three criteria: Land Use (Pasture, Sod, or Citrus) Soil Type (Muck or Sand) Irrigation Method (Microjet or Seepage) Then internal WQ sites were chosen to represent combinations of these criteria.
Three Letter Code: Land Use P-Pasture C-Citrus S-Sod R-Row Crop Irrigation F-Seepage (Flood) M-Microjet S-Sprinkler Soils S-Sand M-Muck Criteria Delineation
Sampling Frequency From 8/6/97 to 6/7/99 Limited by staff time Scheduled to coincide with pumping due to: –Irrigation –Storm Events 3 to 12 total sampling events per site
Results of Internal Sites For internal sites, a TP concentration exceeding mg/L was considered high. Three Sod sites and three Citrus sites exceeded an average TP concentration of mg/L for the study period. These sites are located in the basins for pumps stations PS#4, PS#5, and PS#6.
Average TP Summary for Internal WQ Stations
Characteristics of High Average TP Internal Sites
Field Blocks with High Average TP Extent of blocks with land use, irrigation and soils identical to block at WQ station Primarily muck areas in western portion of farm Sod fields on muck are directly adjacent to PS #4 and PS #5. Citrus runoff has greater distance to travel to discharge pump.
TP Concentration for Sod Sites High degree of variation Higher concentration during wet season Correlation between SAI04 and SAI22
TP Concentration for Citrus Sites SAI05 has high degree of variation SAI05 (west, muck) and SAI11 (east, sand) show opposite temporal fluctuations (unexplained).
Average TP Concentration Summary for Pump Stations Average concentration exceeding mg/L considered high All PSs except #3 exceed this guideline. PS#2, #6 and #7 only slightly exceed mg/L (~ +10%) PS#1 moderately exceeds mg/L (~ +30%) PS #4 and #5 significantly exceed mg/L (over +100%)
Correlation between Internal Sites and their Pump Stations High r value suggests that runoff from blocks at internal site significantly affects discharge TP concentration at PS If % change in TP is -, then internal site may add to TP If % change in TP is +, then internal site may dilute TP
Internal Sites vs. PS #1 Fair visual correlation between SAI15 and PS #1 (not statistically supported) Source of high TP concentration at PS #1 may be SAI19 (need more data to confirm)
Internal Sites vs. PS #4 High r between SAI03, SAI20, SAI22 and PS #4 Low r between SAI04 and PS #4 possibly due to significant dilution effects downstream (possibly SAI03).
Internal Sites vs. PS #5 Few data points High r between SAI17 and PS #5 Short distance between SAI17 and PS #5 = little treatment or dilution (~3% reduction)
Internal Sites vs. PS #6 Fair correlation between SAI11 and PS #6 Significant treatment (reduction) or dilution between SAI11 and PS #6 (~ 65% reduction or 3.2% per 1000 ft.)
PS #1 Annual Average TP Concentration Linear Trend Blue bars meet mg/L guideline Decreasing trend
PS #4 Annual Average TP Concentration Linear Trend Has never met the mg/L guideline Decreasing trend
PS #5 Annual Average TP Concentration Linear Trend Has never met the mg/L guideline Increasing trend
PS #6 Annual Average TP Concentration Linear Trend Blue bars meet mg/L guideline Increasing trend
Conclusion Summary Sources of High TP Concentration are sod fields and citrus on muck soils in west and SAI11 (citrus on sand) in east. High TP sites tend to drain through PS #4, #5, and #6. Sod farming and citrus on muck soils appear to be primary factors contributing to high TP concentrations. A theoretical average dilution/treatment efficiency of 2.7% per 1000 feet of canal distance traveled was calculated. PS #1 through #4, and #7 showed a long term decreasing trend of annual average TP concentration. PS #5 and #6 showed a long term increasing trend
Potential Recommendations Efforts to reduce TP prior to discharge should focus on sod and citrus areas on muck soils in western portion. Efforts to reduce TP at the discharge point should focus on PS #4, #5, and #6. On-site reduction of TP may be achieved by lengthening the travel distance (t.o.c.) between fields and pump. Runoff should be routed through areas of lower TP concentration while maximizing travel distance. Sod fields near PS #4 and #5 are primary candidates for this approach due to their proximity to the pumps.
Total Yearly and Monthly Discharge Data for Sun Ag ( ) Total Yearly and Monthly Rainfall Data for Sun Ag ( ) Total Phosphorus Loads Comparison of TP loads, Pumped Discharge, and TP Concentration Data