Stormwater happens when rain or snowmelt runs along the ground, often picking up sediment and other forms of pollutants, and into rivers, streams and lakes.
Despite the arid climate in much of New Mexico, there can be very large amounts of rain in a short period of time. In addition, New Mexico landscapes often have sparse vegetation and steep topography, and land development creates large areas of impermeable cover from parking lots, streets and sidewalks. All of these factors lead to increased velocity of runoff during storm events, which, in turn, leads to more pollution being picked up by the runoff and discharged into our rivers and streams.
Stormwater and snowmelt pick up contaminants as diverse as leaked motor oil and antifreeze from parking lots, fertilizers, household chemicals, animal waste and hazardous substances from illegal dumping, and carry all that waste into arroyos, rivers and lakes. Many rivers and streams in New Mexico are impaired (polluted) and cannot support some or all of the uses of those waters such as by wildlife, grazing, drinking, or human contact (boating or swimming). In the Albuquerque reach of the Río Grande, for example, stormwater contributes several billion gallons to the Río Grande and is the major source of E. coli and polychlorinated biphenyls (PCBs) in the river.
The Clean Water Act (CWA) became law in 1973, with extremely optimistic goals: to have all waters “fishable and swimmable” by 1983 and to eliminate all discharges of pollutants into the water by 1985. While the CWA has substantially improved water quality, it had a major flaw: it was focused on controlling “point sources” of pollutants—typically, industrial sites and wastewater pipes. The CWA historically ignored nonpoint sources such as runoff from agricultural fields and urban areas, except for encouraging the use of “best management practices” (BMPs) to minimize the quantity and quality of runoff. More recently, a small portion of this runoff has been regulated by the CWA through stormwater permits, which, instead of encouraging BMPS, require their use.
Most effective BMPs rely on what are called “green infrastructure” and “low-impact development” (GI/LID) solutions to control stormwater runoff. These management approaches and technologies generally require that post-development hydrology be as close as possible to pre-development hydrology through the use of practices that mimic natural processes, with a focus on maximizing infiltration, evapotranspiration, and capture and reuse of stormwater.
In addition, GI/LID practices seek to accomplish these objectives:
- Protect areas with natural ecological functions
- Remove impervious cover and use permeable pavements
- Increase bioretention
- Utilize green roofs and walls, cisterns, and rain barrels
- Create green buffers
There are a growing number of innovative GI/LID projects in New Mexico.
Los Alamos National Laboratory (LANL) has had a serious stormwater-contamination problem since it began operations nearly 60 years ago. After years of data collection and independent analysis, Amigos Bravos and its community allies sued LANL over its stormwater management. A negotiated settlement led to a fund for technical experts to work with LANL’s environmental-management staff to rethink how the Lab manages stormwater, shifting from simplistic small-scale solutions to a more holistic and sustainable approach. If LANL’s environmental budget is kept at an adequate level, these new approaches could become a model for remediating toxic sites across the arid West.
In Taos County, there is significant contamination of the rivers in the watershed, in large part because of stormwater runoff from both urban and heavily grazed areas. After years of discussions, the county now has a proposal to create buffers where construction and storage of hazardous materials are restricted along all rivers and streams in the county. In addition, a watershed plan for the Río Pueblo de Taos has been drafted that encourages GI/LID practices in road maintenance and construction.
In the Middle Río Grande, the Environmental Protection Agency (EPA) has been developing a pilot watershed-based, Municipal Separate Storm Sewer System (MS4) stormwater permit. While each of the entities in the Middle Río Grande will still have their own stormwater permit, the watershed-based MS4 permit is meant to encourage larger-scale solutions, collaborations and cost-savings for water-quality monitoring and public education and outreach. While seeking to adjust permit requirements to encourage innovation, the permit targets the primary sources of E. coli and PCBs with more aggressive deadlines and goals.
In 2012, the first urban national wildlife refuge in the Southwest was dedicated at the site of the old Price’s Dairy in the far South Valley. The Valle de Oro National Wildlife Refuge has a novel component: the inclusion of a major stormwater facility running across the site. AMAFCA, the Albuquerque Metropolitan Area Flood Control Authority, will collect stormwater that has plagued the South Valley for decades and use it to support creation of wetlands and wet meadows in the refuge, which will help improve water quality and realize a refuge goal of restoring the site to something more closely resembling the mosaic landscape that existed prior to all the engineering on the river.
These four examples of communities taking steps to protect their waters from runoff pollution provide important models for other communities throughout the state. All climate-change predictions for New Mexico warn of an increase in large and, in some cases, catastrophic, storm events. In the face of these predictions, implementation of LID/GI practices provides the most effective way to protect human health and the environment from toxic stormwater runoff.
Michael Jensen is Amigos Bravos’ Middle Río Grande Projects director. Since 2005 he has been representing AB on issues related to water quality in the Middle Río Grande. He works on projects that address stormwater discharges, impacts from dairies on water quality and efforts to improve water quality monitoring.