Timing is Everything: Planning Wastewater Facilities for the South Adams County Water and Sanitation District

The South Adams County Water and Sanitation District (District) is located in the northeastern part of the Denver metropolitan area and serves the City of Commerce City, Colorado (City) with potable and irrigation water, as well as providing sanitary sewer collection and treatment. Construction of the nearby Denver International Airport, Interstate E-470, and large tracts of undeveloped land close to downtown Denver has made the area the District serves an attractive prospect for rapid development. Black & Veatch Corporation (Black & Veatch) has been working with the District for over twelve years on planning and phasing improvements associated with the District's wastewater collection and treatment facilities. Developer interest began in the late 1990s and population growth projections were originally in excess of 2,000 homes per year with the District's customer base projected to grow from 25,000 to 95,000 within 20 years. The District quickly decided that they would need to take a proactive approach to managing the rate of growth and required infrastructure improvements. In 2001, a Wastewater Master Plan and Utility Plan (similar to a 201 Facility Plan) were completed for the District. These documents resulted in an aggressive capital improvements plan. Black & Veatch and the District, however, wanted to construct facilities in such a way that existing facilities and options were maximized to avoid building facilities and then encountering an economic bust or change in development plan that would leave the District with oversized or mislocated facilities. To address this situation, population and flow trends have been closely monitored for the last 10 years. During this period, Denver has experienced a 100-year drought, an economic slow down, and uncertainty in the planning and location of required long-term wastewater treatment facilities. In addition, the District has collected additional data in specific portions of their collection system to improve understanding of wastewater flow within the system. Over time, the District has seen a decrease in per capita flows and gained a better understanding of the location and cause of infiltration and inflow in their system allowing improved hydraulic modeling of the system. The District's measured approach to master planning and undertaking capital improvements projects has resulted in: a better understanding of the operation of existing facilities, the limitations of growth and flow projections, and the benefits of ongoing planning to maximize economic benefit.