The middle Rio Grande watershed based MS4 permit - Case Study

ALBUQUERQUE MS4 – THE EARLY YEARS

In the early years of its permit history, the Albuquerque Metropolitan Arroyo Flood Control Agency (AMAFCA) operated with a typical MS4 Phase I, individual permit that included Minimum Control Measures along with Best Management Practices to enhance water quality including:

• Public education and outreach
• Public participation and involvement
• Illicit discharge detection and elimination
• Construction site runoff control
• Post-construction runoff control
• Pollution prevention/good housekeeping

Monitoring was conducted under permit compliance and in support of MS4 operations. Patrick Chavez, AMFACA’s Stormwater Quality Program Engineer, is responsible for developing and maintaining the Agency’s Stormwater Monitoring Program (SWMP).

The conventional NPDES permitting approach provided little consideration of upstream sources except as background concentrations of a pollutant. Often, attainment of water quality standards and other water quality goals was independent of addressing upstream pollutant contributions. The limited data provided by grab sampling made it difficult to determine whether BMP’s were effective in supporting water quality standards defined by the EPA.

EPA ANNOUNCES THE WATERSHED BASED PERMIT

In 2009, at the request of EPA, the National Research Council (NRC) published a report entitled “Urban Stormwater Management in the United States”. In the report, The NRC determined that the framework for addressing sewage and industrial wastes within the Clean Water Act was not well suited to the more difficult problem of stormwater discharges, and recommended that EPA make fundamental changes in the current management of stormwater including switching to a watershed based permitting approach.

As a first step, the NRC suggested the EPA create a pilot program that would allow them to explore the many complexities of watershed-based permitting (WBP). Some of the pilots’ goals included implementing mechanisms to better tailor stormwater management plans and stormwater permits to meet the needs and conditions of the selected watersheds. In addition, the pilots would document efficiencies to be gained by the permitted entities in implementing certain elements of the stormwater program, e.g., education, outreach, and monitoring.

The EPA announced three pilot areas selected to explore watershed permitting concepts for stormwater management. The Middle Rio Grande (MRG) valley (see map in Figure 4) was chosen as one of three pilot Watershed Based Permit (WBP) projects nationwide because of existing water quality impairment in the Rio Grande and the opportunity to work on the challenges of permitting unique to arid and semi-arid parts of the country.