Page 2 of 3
Most of the cleanup is split into two stages. Stage 1 requires local governments to tally all nutrient sources added by development since 2006. Cities then must build stormwater capture systems or rain gardens or fix failed septic systems to redeem nutrient credits. Cities also have to spend tax dollars to correct for development that, although legal, was constructed under local standards that were not strict enough to protect the lake.
At the end of Stage 1, the lower end of the lake southeast of Highway 50 is expected to meet the Clean Water Act. The upper end of the lake, above Highway 50 and near Durham, is expected to improve.
Stage 2 requires further pollution reductions intended to bring the entire lake into compliance with the Clean Water Act.
A rule was written for each source of nutrient pollution. For example, the agricultural rule calls for an increase in sustainable practices, such as leaving more land untilled and fencing animals out of streams.
The new development rule restricts the annual number of pounds of nitrogen and phosphorus that are allowed to run off a finished property. Developers will have to use some land to construct ponds and rain gardens to slow runoff and capture those nutrients. That may force developers to build fewer homes per acre, Frank Thomas with the Home Builders Association of Durham, Orange and Chatham Counties, said, increasing sprawl. But, Bill Holman of Duke's Nicholas Institute wondered, will "we continue to sprawl around the region or are we going to build up in some places?"
The use of reclaimed wastewater to irrigate fields and golf courses and support industrial processes, instead of dumping it into streams, will help municipalities meet the sewage treatment requirement. The city of Durham offers reclaimed water for pickup, if customers have been trained by the city on how to use it and accept at least 250 gallons. Raleigh has a 21-mile reclaimed water distribution system that the city plans to extend to more than 100 miles.
The sewage treatment rule limits the amount of nitrogen and phosphorus released by the Hillsborough, South Granville Water and Sewer Authority, and Durham Northside treatment plants. Durham had already budgeted $17 million for upgrades that should bring it into compliance with the first stage of the rules. But as Durham grows, it will have to treat a higher volume of sewage. A 2010 memo from Voorhees and Sindelar to Durham City Manager Tom Bonfield reported an estimated cost in 10 to 15 years of $80 million–$320 million to remain within the Stage 1 standard, depending on Durham's population growth. It is too soon to say how difficult or expensive it will be to meet Stage 2 requirements in 2036. Total cleanup costs are estimated at a minimum of $567 million, just for Durham.
Water and sewer rates will likely increase to offset some of the cost, although local governments can apply for state and federal grants to pay for some of the upgrades.