Contaminated Sediment: Appellate Court Muddies the Water for TMDLs

On March 30, a short opinion from California’s Second Appellate District raised a long list of unanswered questions in a case concerning a Regional Water Quality Control Board’s authority to develop a Total Maximum Daily Load (“TMDL”) for contaminated sediment.  (A TMDL is a regulation that calculates the maximum amount of a pollutant an impaired water body can receive and still meet water quality standards, and allocates the loading among the various sources of that pollutant.)  In Conway v. State Water Resources Control Board , (March 30, 2015), the Court considered whether the Regional Board properly adopted a TMDL for McGrath Lake in Ventura County to address the in situ concentration of pollutants in lake bed sediment.  The Court upheld the TMDL based upon its finding that “lake waters and the lake bed sediment form a single physical environment,” other factors unique to McGrath Lake, and the Regional Board’s broad discretion to select an appropriate measurement for expressing a TMDL.  While it is unclear whether the Court’s holding will extend beyond McGrath Lake, parties subject to future sediment TMDLs should take note: Conway illustrates the difficulty of using TMDLs to address in situ contamination in sediment, and also raises complicated issues regarding the parties responsible for implementing the pollutant load reductions.

In October 2009, the Los Angeles Regional Water Quality Control Board adopted an amendment to its Basin Plan to incorporate a TMDL for pesticides, polychlorinated biphenyls (“PCBs”), and sediment toxicity in McGrath Lake.  According to the Regional Board, these impairments are primarily caused by agricultural runoff from external sources and in situ sources of pollutants in the lake bed sediment.  With respect to the contaminated sediment, the Regional Board found that high concentrations of pesticides and PCBs in the sediment can release contaminants into the water column through a process called desorption and impair the lake’s beneficial uses, a component of water quality standards.  The Regional Board therefore expressed the TMDL as a concentration of pollutants in the lake bed sediment.  The responsible parties, which include the appellants in Conway, are required to enter into a Memorandum of Agreement with the Regional Board to voluntarily remediate the lake bed sediment in order to achieve the target concentrations for each pollutant (which are referred to as load allocations in the McGrath Lake TMDL), or the Regional Board will take enforcement action to compel cleanup.

The appellants filed a petition for writ of mandate challenging the Basin Plan Amendment.  They argued, in part, that the Regional Board could not set a load allocation solely based on the concentration of pollutants in lake bed sediment because the lake bed sediment is not part of the receiving water.  The trial court denied the petition and the Court of Appeal affirmed.  In its opinion, the Court concluded that the lake is both its water and its sediment: “the sediment is wet, it is intermixed with the lake waters and it is part of the lake.”  The Court also noted that “one can discharge a pollutant from one part of the receiving waters into another part of the same receiving waters.”  Upon acknowledging these principles, the Court explained why a concentration-based TMDL for sediment was reasonable and appropriate.

Pursuant to 40 C.F.R. § 130.2(i), “TMDLs can be expressed in terms of either mass per time, toxicity, or other appropriate measure.”  The Court found that the language “other appropriate measure” gives the Regional Board broad authority to express the McGrath Lake TMDL in terms of concentrations of pollutants in sediment, so long as the method is reasonable.  The Court determined that the Regional Board’s method for setting the McGrath Lake TMDL was indeed reasonable.

The Court’s approval of the McGrath Lake TMDL raises interesting questions regarding TMDLs for contaminated sediment.  For example, the opinion illustrates how the Clean Water Act’s TMDL program is not well-suited to regulatein situ pollutants in sediment.  Where, as here, the load allocations are intended to drive remediation of the contaminated sediment rather than reduction of the loading from external sources of pollutants, a Cleanup and Abatement Order under Water Code section 13304 seems more appropriate to address the remediation than a TMDL.  In fact, it seems clear the Regional Board will resort to these State law procedures if the voluntary MOA approach does not work.  Moreover, the goal of remediating the sediment to achieve the load allocations is more akin to achieving a specific cleanup level or numeric water quality objective.  The Regional Board would normally be required to consider cost effectiveness and economics under State Water Board Resolution 92-49 and Water Code section 13241(d), respectively, when establishing cleanup levels and water quality objectives.  However, using the TMDL to establish the load allocation may allow the Regional Board to avoid or minimize consideration of cost effectiveness and economics.  (See City of Arcadia v. State Water Resources Control Board (2006) 135 Cal.App.4th 1392, 1413-18.)

In addition, the Court’s statement that “one can discharge pollutants from one part of the receiving waters into another part of the same receiving waters” is problematic.  The Supreme Court has twice ruled “that the transfer of polluted water between ‘two parts of the same water body’ does not constitute a discharge of pollutants under the Clean Water Act.”  (L.A. County Flood Control Dist. v. Natural Resources Defense Council (2013) 133 S.Ct. 710, 713 (quoting South Florida Water Management Dist. v. Miccosukee Tribe of Indians (2004) 541 U.S. 95, 109-112).)  This rule undermines the Court’s conclusion that desorption of pollutants from sediment is a discharge into the receiving water, if the receiving water is comprised of both the water and its sediment.

Issues of responsibility for sediment contamination are growing increasingly contentious, as evidenced by the City of San Diego’s recent lawsuit against Monsanto for contaminating San Diego Bay with PCBs, including the Bay’s sediment.  As a result, parties subject to a TMDL for contaminated sediment should participate in the TMDL’s development to influence how the TMDL is expressed and examine whether a TMDL based solely on in situ sediment contamination is appropriate or reasonable under the circumstances.