Alafia river is the important, active and viable river in Hillsborough County and the length of the Alafia River is 25 miles within the Atlases. (Alafia River Watershed Excursion). Geographically it originates from West Central of Polk County and flow towards to west direction of Hillsborough County. It is surrounded by Hillsborough river on the north, in the south by Little Manatee river and in the east by Peace river basin. North Prong, South Prong, Turkey Creek and Little Alafia river are the major tributaries of the Alafia River. The topography of the river falls under the South Western District of Florida. The climatic conditions of the river is subtropical and the average annual rainfall is 44.9 inches. It has average summers of 89.9° F and average winters of 72.8° F. (Polk County Water Atlas). The soil type of the river is sandy, shelly and clayey. Industrial waste, Agriculture waste, Mining waste and land development are the causes of the water pollution in the Alafia River. 30% of the world’s phosphate supply comes from the ‘The Alafia’s Bone Valley”. The size of the watershed is 270,000 acres and it is the largest watershed in Hillsborough County. The population in the Alafia watershed is almost 117,000 people and 17% of the Alafia Watershed Area is under protection. (Alafia River Watershed Excursion. Water Atlas has the data of water quality of the Alafia River over the years. From 1932 to 2018, this water resource is monitored by 162 sampling locations and a total of 2,922,137 samples were tested. The Preliminary Goals for the development and management of the waterbody are: water quality, flood protection, natural systems, water supply, protect, preserve and restore the Alafia river basin and estuary.
(Alafia River Map: Tampa Bay Water Org)
In this study we selected the Alafia River Tidal Reach above Hillsborough Bay and the quality of the water is analysed by studying the Water Atlas collected and stored data. The length of the selected waterbody is 7.5 miles. The waterbody starts from Buckhorn Creek downstream to the mouth of the river. The watershed comprises of 5504 acres i.e., 8.6 square miles and land use falls under urban and built up area of 3228 acres, agriculture of 478 acres and 825 acres of water. The estuary of the river is identified as (Waterbody Identification number) WBID 1612G. This data gives us the information about the nitrogen, phosphorous, mercury and dissolved oxygen and nutrients total maximum daily load levels in the selected Alafia River Tidal Reach above Hillsborough Bay Waterbody. The waterbody is considered as Impaired Waterbody. Integrated Water Resource Management (IWRM) methodology is used to evaluate the water quality impairments. Dissolved Oxygen and nutrients assessment impairment is also done by IWR methodology. The value of the impaired dissolved oxygen and nutrients and the value of the mercury present levels and the required limits will be provided in the following sections. By studying the data the water body is falls under category III which represents recreation, propagation, and maintenance of a healthy well-balanced population of the fish and wildlife.
Stakeholders plays a crucial role in developing a certain organization or any institution. If we consider stakeholders contribution in managing the water bodies is crucial and its treated as important for restoring the water body by by regulating, safeguarding, monitoring, policy making and works on the objectives. Stakeholders include local public, local and regional government agencies, employees, directors and the business people who depend on the product and do business. Here in this waterbody case the identified key stakeholders are District’s Alafia River Basin Board (DARBB), local governments, communities falling under Alafia river, The Alafia River Stewardship Council (ARBSC), The Alafias watershed land and water linkage task force (Task Force), Department of environmental protection, department of agriculture and consumer Services, the Florida Fish and Wildlife Conservation Commission, Tampa Bay Regional Planning Council, Army Corps of Engineers, Tampa Bay estuary program, Hillsborough County, Hillsborough County Environmental Protection Commission, Hillsborough County City-County Planning Commission, Polk County, Tampa Bay Water, Cargill, CF Industries, and others.The Public Outreach can be done by following the certain procedures like Alafia River Basin Management Action Plan, Best Management Practices Community Meetings, Social Media Campaign, Community Services, Carrying out monitoring to track plan effectiveness, Public education and outreach, Public participation and involvement, Illicit discharge detection and elimination, Construction site runoff control, Post construction runoff control, Pollution control and good housekeeping. In this paper we followed all the 9 EPA Elements, discussed, analyzed and the results are given in the following sections.
Identify causes and sources of pollution that need to be controlled:
The Florida Department of Environmental Protection (FDEP) is charged with developing Total Maximum Daily Loads (TMDLs) that identify the needed reductions in pollutant loads such that impaired waterbodies may be restored and achieve their designated uses. The general issues of concern of the Alafia River waterbody are salt intrusion due to drought conditions, mercury, phosphate spills, phosphate mining along the shore, heavy rain runoff , toxic waste spilled into the river, decrease in the rivers fish and vegetation, careless water management, and unplanned development and land development. To make it precise, we concentrated on studying the preliminary indicators or stressors like the mercury and dissolved oxygen & nutrients. There are so many factors that affect the dissolved oxygen and mercury in the waterbody segment.
In this waterbody segment photosynthesis produces oxygen and it is consumed by the plants, animals and anaerobic bacteria. Then chemical, oxidation and reduction reactions are done by interacting the brackish water with sunlight, humic and fulvic materials. The absorption of the oxygen from the atmosphere depend on the depth of the water level and turbulence. Nutrients and phosphorus ignites the growth of the algae and the excess algae leads to increase the concentration of dissolved oxygen (DO) in the water and this happens generally in the daylight and once the contrary the DO is reduced in the night due to the respiration done by the algae. The surface water in Florida is protected based on the use classification of the water and this waterbody falls under use classification Class III. The interpretation of the dissolved oxygen shall not be less than average 5.0 mg/L. The daily and seasonal fluctuations of dissolved oxygen above 5.0 mg/L level should be maintained and restored. The sources of impairment are point sources and nonpoint sources. Point sources like domestic and industrial wastewater treatment facilities and nonpoint sources like rain water runoff, agriculture, stormwater runoff, runoff from urban and land uses, discharge from septic systems and atmospheric deposition. (Division of Environmental Assessment. (2014, April)).
Florida water is tested for Mercury levels in the fish and the results are elevated and addressed in Florida’s Statewide Mercury TMDL. In 1999 CD 102 water bodies are listed as impaired like streams 63, lakes 13 and estuaries 26. Since then fresh water in Florida, almost all coastal and estuarine are identified as impaired by sampling the fish tissue. There are still freshwater bodies need to be tested for mercury levels in Florida. The main source of mercury is accumulating from atmosphere deposition is 70%. It include emissions from burning coal and fossil fuels, volcanoes and forest fires contributing to remaining 30%. Coming to Mercury levels, the total mercury concentration in ambient water should be less than 0.012 µg/L (12 ng/L) for Class I and Class III freshwater water bodies, should be less than 0.025 µg/L (25 ng/L) for Class II and Class III marine water bodies, and should be less or equal to 0.2 µg/L (200 ng/L) for Class IV and Class V waters [per 62-302.530(41), F.A.C.] Human risk from environmental exposure to mercury is almost exclusively through exposure by the consumption of fish with elevated levels of mercury. For general population, the consumption guideline is 0.3 ppm and for women of childbearing and young children population, the consumption guideline is 0.1 ppm. Florida water is mixed with 0.5% of total mercury load or 23 kilograms every year from industrial and domestic wastewater. This is permitted by National Pollutant Discharge Elimination System (NPDES) PERMITS. EPA has set permissible limits for Methylmercury MeHg and Hg levels and ⅔ of the freshwater in Florida is exceeded 0.077mg/kg of MeHg and 0.3% of Hg. (Department of Environment Protection. (2013, October 24)).
Determine load reductions needed:
The TMDL Dissolved Oxygen Components Expressed as a Daily Load for The Alafia River Tidal Segment (WBID 1612G) TMDL 0.65 mg/L: WLA: Wastewater 14.3 lbs/day, NPDES Stormwater 54% reduction, LA 54% Reduction, MOS: Implicit. (Annually 5410 lbs / annually).