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128 A P P E N D I X B Sample Unit Area Load Results from SELDM Model California TMDL (Los Angeles River) The SWRCB adopted the National Pollutant Discharge Elimination System (NPDES) Statewide Storm Water Permit Waste Discharge Requirements (WDRs) for State of California Department of Transportation (Order WQ 2012-0011-DWQ, as amended by Orders WQ 2014-0006-EXEC (January 17, 2014), WQ 2014-0077-DWQ (May 20, 2014), and WQ 2015-0036-EXEC (April 7, 2015)) (Caltrans NPDES Permit), published September 19, 2012, effective July 1, 2013, and revised on April 7, 2015. This permit includes Attachment IV (TMDL Requirements), which identifies the TMDLs where Caltrans is required to implement control measures for the impaired water body. Caltrans is designated as a stakeholder in 84 TMDLs. As a part of the unit area load analysis from SELDM, the Los Angeles River watershed was selected, since this water body is listed as impaired for metals, bacteria, and trash in the Caltrans NPDES Permit. However, all constituents except for trash were analyzed in SELDM. Washington State TMDL (Lake Campbell) Washington State DOTâs TMDL Implementation Plan is part of its MS4 permit, it identifies the TMDLs, and describes their respective action items, and schedules (WSDE 2012). The new DOT MS4 permit that was issued in February 2009 includes nine TMDLs. The receiving water impairments are for dissolved oxygen, temperature, mercury, arsenic, pesticides, PCBs, nutrients, fecal coliform, and pathogens. The Washington State Department of Ecology listed Lake Campbell as impaired for phosphorus under Section 303(d) of the Clean Water Act due to the lake's inability to support its beneficial uses. Most of the adopted TMDLs within the state are for bacteria, nutrients, or temperature. Due to excessive phosphorus and other nutrient inputs from the watershed, algae have bloomed within Lake Campbell and resulted in limited recreational activities. As part of the unit area load analysis within SELDM, Lake Campbell was analyzed for an estimate of highway unit area loads within Washington State. Lake Campbell is adjacent to State Highway 20, which may be a potential direct influence on the lake and its impairment. Additionally, the load results indicate that Lake Campbell watershed has the highest unit discharge of chloride loads from highways when compared to other regions and states with higher precipitation.
Sample Unit Area Load Results from SELDM Model 129 Florida State TMDL (Lower St. Johns River) Florida State DOT (FDOT) implements its stormwater program through the NPDES permit issued by the Florida Department of Environmental Protection. FDOT coordinates directly and early in the TMDL development phase with the Department of Environmental Protection (DEP) to review all WLAs assigned to the DOT. FDOT is named in a variety of TMDLs statewide for pollutants such as nutrients, phosphorus, and fecal coliform. The Florida Department of Environmental Protection and St. Johns River Water Management District (SJRWMD) collaborated on the development of the Lower St. Johns River Nutrient TMDL. The nutrient TMDL was developed December 3, 2003 and approved by U.S. EPA on April 27, 2004. After further analysis, additional water quality problems were noted within the river, which indicated nutrient impairments such as fish kills, algal mats, and low benthic animal diversity. As part of the unit area load analysis for this river, SELDM was used to estimate all types of constituent loads (Table 20). The high quantity of loads for this water body can be attributed to the largest amount of average annual precipitation monitored for this region. St. Johns River is a large water body that comingles with major highways in urbanized areas, potentially resulting in a direct impact to the water body from highways. Massachusetts TMDL (Charles River) The Massachusetts Department of Environmental Protection worked closely with the US EPA to develop a phosphorus TMDL to restore the Charles River's beneficial uses and reduce algae levels. A majority of the state's impaired water bodies are listed for nutrients and pathogens. The Massachusetts DOT (MassDOT) has developed a Stormwater Management Plan (SWMP) that describes their protocols to address stormwater and water quality issues. The SELDM results for the Charles River unit loads revealed that sediment, nutrients, and chloride loads should be a primary concern for MassDOT. In the forthcoming chapters, discussions on developing strategies for DOTs to comply with these critical constituents are presented. Table 52 identifies the typical average annual rainfall determined by the model based on the location of each unit area. Table 52. Annual watershed precipitation. TMDL Average Annual Precipitation (in/year) California TMDL (Los Angeles River) 13.81 Washington TMDL (Lake Campbell) 38.38 Florida TMDL (Lower St. Johns River) 44.8 Massachusetts TMDL (Charles River) 39.58
130 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff Table 53 presents the results of average annual unit area loads from highways for specific water bodies from the model. Table 53. Annual unit area loading for highways (all AADT) within various states. Constituent Unit California Washington Florida Massachusetts TSS lbs/ac/yr 346.55 863.09 991.07 919.48 TN lbs/ac/yr 6.53 16.87 22.33 17.17 TKN lbs/ac/yr 5.38 12.57 15.24 13.72 NOx as N lbs/ac/yr 2.22 5.37 6.22 5.9 TP lbs/ac/yr 0.65 1.92 2.13 2.02 DP lbs/ac/yr 0.29 0.73 0.92 0.83 Aluminum lbs/ac/yr 14.53 41.18 46.79 41.26 Arsenic lbs/ac/yr 0.0082 0.017 0.02 0.02 Cadmium lbs/ac/yr 0.0018 0.0048 0.0058 0.005 Copper lbs/ac/yr 0.098 0.26 0.30 0.26 Iron lbs/ac/yr 4.83 13.61 14.55 12.61 Lead lbs/ac/yr 0.55 2.09 2.48 2.21 Mercury lbs/ac/yr 0.00045 0.0015 0.0017 0.0014 Zinc lbs/ac/yr 0.62 1.47 1.82 1.66 E. Coli MPN 12,586,206 365,727,272 464,966,666 419,689,655 Fecal Coliform MPN 950,000,000 2,093,272,727 2,392,366,667 2,508,103,448 BOD lbs/ac/yr 38.103 87.21 103.61 101.6 Cl- lbs/ac/yr 188.10 514.33 503.87 439.55 TDS lbs/ac/yr 239.31 582.03 681.37 580.62 *Concentrations from Highway (all AADT) were used to estimate pollutant loads. The values presented in Table 53 can be used by the four analyzed states as a baseline to develop preliminary estimates of the priority pollutant loads for DOTs. The model can be used by other DOTs to identify their applicable preliminary baseline loads. Note that arsenic, cadmium, and mercury have lower discharge loads from highway land use types. This result is attributed to a lower concentration of these constituents from highway land use types. Additionally, higher annual precipitation levels within the southeast region result in higher unit area loads for the analyzed constituents when compared with loads for the same constituents in the western region. Also, the model results indicate that the highest pollutant load discharge from highway land use types is total suspended solids and total dissolved solids. Therefore, these two constituents should be critical pollutants that are prioritized by DOTs for prevention. All four of the regional SELDM runs indicated that the primary pollutants of concern for highways are sediment, nutrients, chloride, and BOD. In chapters 4 through 6, the research team prioritized methods for developing strategies for DOTs and compliance alternatives to address primary POC.
