493541137Every summer, warm weather prompts millions to flock to bodies of water. While sunbathers likely give little thought to the source of water in which they frolic, design professionals and builders of public and private projects must pay careful attention to how construction will affect stormwater that eventually finds its way into lakes and oceans. Stormwater runoff is rain or melted snow that runs across, rather than seeps into, the ground. Runoff can cause severe damage. Without any type of treatment, runoff also pollutes tributaries and major waterways. Improper design, faulty construction or lack of maintenance of stormwater management systems can create professional exposure to unexpected avenues of liability.

Detention ponds have become popular in commercial and residential building. Unlike retention ponds, which remain dry except to capture water briefly and slowly release it, detention ponds are always filled with water. Detention ponds have a number of benefits, including aesthetic appeal, and are useful in reducing runoff pollution. Design considerations include analysis of the topography of the land; how well soil will hold water; the shape, size, depth and slope of the pond and shoreline; planting of proper vegetation along the shoreline; and quality and placement of materials surrounding the pond, including pipe and concrete. In other words, exposure to liability at this phase may be significant but does not end there.

Post-construction ponds require heavy maintenance of both the water and the shoreline, including upkeep of vegetation strengthening the banks. Determining who has the burden of maintenance is state- and municipality-specific; generally, it is the local government or the property owner/ homeowners’ association. Potential claims from a failed pond may be far-reaching, extending to the owner for improper maintenance or to a design professional who may have consulted on any aspect of the construction of the pond (up to and including the vegetation selected).

In May 2014, the decision by the U.S. Supreme Court to let a Ninth Circuit appeal go unheard further complicated the legal landscape. In Natural Resource Defense Council, Inc. and Santa Monica Baykeeper v. County of Los Angeles et al., the Ninth Circuit ruled that the County of Los Angeles was liable for allowing pollution in runoff to flow into navigable waterways and ultimately into the Santa Monica Bay and Pacific Ocean. The County is made up of 88 cities and 140 unincorporated municipalities. Each of the cities has its own National Pollutant Discharge Elimination System Permit, which acts as a contract under the Clean Water Act to regulate how much pollution can be discharged. Although the permits are specific to each municipality − most of the stormwater management system is interconnected − it’s impossible to determine the allocation of liability related to the points at which stormwater runoff is being polluted in excess of allowable pollution discharge.

My home state, Pennsylvania, posts an electronic copy of the “Pennsylvania Stormwater Best Management Practices Manual.” Most states and some major cities also publish a guide. It would be prudent for any design professional who is thinking about “riding the storm” (or performing services related to the design or construction of a stormwater management system) to consult the applicable manuals.