What Happens on the Land Happens to the Water

This post is part of an ongoing series on the midpoint assessment and long-term goals of the Chesapeake Bay cleanup effort.

In my last post, I described how a database housed by the Maryland Department of the Environment allows tracking of land development activities in real time. This database not only gives us the ability to track the recent scale and pattern of habitat destruction in Maryland, but it also can be used by regulators to build a tool that will allow the state to meet its commitment under the Chesapeake Bay restoration framework to account for and offset the growth in Bay pollution from new sources. 

From a water quality perspective, land conversion involves two potential problems. The first problem comes from the destruction of the pre-development landscape, which is often natural and helps capture rain and filter pollutants before they can run off into the nearest surface waters. The second problem involves whatever pollution is generated from the new use of the land, particularly any newly paved surfaces. 

The land use before and after development makes an enormous difference for water quality and the local ecosystem. Scientists studying the Chesapeake watershed know that large tracts of old forest contribute the least pollution of any landscape, exporting nitrogen pollution at a rate of only about two pounds per acre. By contrast, the rates of nitrogen loss from paved roads and some types of farm fields can be more than ten to fifteen times greater, at more than 30 pounds per acre (the fertilizers used by farms – nitrogen and phosphorus – are the same as the main pollutants to the Chesapeake Bay and other estuaries). 

On one end of the land conversion spectrum would be a development that converts acres of undisturbed forest or other natural areas near a tidal tributary into a residential subdivision served by septic systems. On the other end of this spectrum would be conversion of cropland that had been receiving excessive amounts of manure or fertilizer into a single home connected to an advanced wastewater treatment plant, with trees planted and built with environmental site design features to reduce runoff. 

In the former case, nearby waters would lose a high-value pollution-absorbing asset in exchange for a significant new source of pollution emitted by septic systems, rooftops, and driveways – turning a large asset into a large liability from an environmental perspective. In the latter case, water quality could theoretically benefit as post-development pollution drops significantly. Although a recent analysis of development over a one-year period showed a significant number of projects that converted pasture or crop lands, which generally produce a greater amount of nutrient pollution per acre than other land uses, often the post-development land use is sprawling residential or commercial projects that generate a similar or greater amount of pollution for local waterways and, ultimately, the Chesapeake. 

It is also important to note the proximity of any development to the nearest waterway in order to measure the impact on the Bay's network of streams and on drinking water for nearby communities. Lands closer to waterways obviously deliver a higher percentage of their pollution to the water, while development further away may have much less impact as pollutants tend to be filtered and attenuated by movement through soils. Given that Maryland has a dense drainage network of more than 10,000 miles of perennial streams and rivers, it is not surprising that many projects in this analysis were found to be located near a stream and will become a significant new source of water pollution. 

Maryland Needs A New Growth Offset Policy Now 

We now understand, scientifically, what our development patterns do to our water quality. What is needed are new policy tools that account for the impacts of growth and create incentives that steer projects into locations that make sense for water quality and for overall environmental and fiscal sustainability. But we need these tools now before yet another year of development converts even more of our scarce natural areas to urbanized or industrial landscapes. 

In the year since the geospatial analysis described in the previous post was completed, an even greater number of new developments were proposed. Between November 2015 and November 2017, more than 2,200 projects were proposed throughout the state that would disturb more than 21,000 acres. Additional applications continue to come in by the day while we wait for the state to develop an effective offset policy. 

Maryland has been in the process of developing a pollution growth offset policy for the better part of a decade. This process was initially driven by the Bay TMDL but also responds, in part, to subsequent state legislation requiring regulations to offset nutrient pollution from new sources. Under former Governor Martin O'Malley, an Accounting for Growth workgroup of stakeholders met a number of times in 2013 and produced a final report, only to see the process fall short of adopting final regulations before O'Malley left office. 

The current administration under Governor Larry Hogan has rebranded the effort Aligning for Growth, but despite a few meetings with stakeholders and the development of "guiding principles" and a couple discussion drafts, not much progress has been made on new regulations. Whenever the Department of the Environment moves forward in proposing growth offset regulations, several issues bear watching to make sure the policy is suitably comprehensive and protective. 

First and foremost, the regulations must clearly and explicitly address growth in all forms, or at the very least for each of the major source sectors recognized under the Bay TMDL. As noted by EPA in its recent evaluation of Maryland's progress under the Bay TMDL, this must include animal manure and agricultural pollution generally. Any policy that does not account for the potentially substantial growth in nitrogen and phosphorus pollution from the significant increase in farm animal (poultry) populations would fail to adhere to EPA's expectations under the Bay TMDL and ignore what is likely to be the largest source of new pollution in Maryland. Just one new modern chicken house has the potential to generate more than 3,000 pounds of phosphorus per year, which is on par roughly with the amount of phosphorus pollution reduced by an average wastewater treatment plant upgrade costing Marylanders $5 million to $10 million each. Unfortunately, it appears that the state may be planning to defer action on developing an offset policy for agriculture while focusing on stormwater and septic system pollution in urban and suburban areas. 

The second potential pitfall, judging from early discussions of the future growth offset regulations, is an approach that considers only net growth balanced over a broader geographic scale, as opposed to offsetting growth on a case-by-case basis, wherever it occurs. The issue with considering a growth offset policy that focuses on a broader scale is that it could allow any number of large and polluting projects to be developed as long as they occur within the same large area as other projects that convert higher polluting landscapes, generally crop land. This policy would incentivize the destruction of scare agricultural land in quickly urbanizing Maryland while doing nothing to offset the pollution associated with many new projects that convert forests and other scarce and valuable natural landscapes. 

The best solution is to require any and all pollution associated with a new development to be offset. If a farmer sells agricultural land for development and the post-development landscape happens to generate less pollution, then in this limited scenario, the developer should not need to purchase any offsets. But in most other scenarios, land development becomes a new source of nutrient and sediment pollution to local waterways and the Chesapeake Bay. Those proposing to develop the land should be the ones to pay to offset the pollution they create, rather than foisting that burden onto the public and negating the impact of investments in Bay restoration projects that Maryland taxpayers have been making for decades.

Thanks to the scientists and modelers at the Chesapeake Bay Program, we now have the tools to understand the impact of development on water quality. And as I have shown, the Department of the Environment's e-Permits database is a powerful tool for tracking new developments, which can also be modified to allow for the calculation of pollution offsets for individual projects. The only thing left to do is proceed expeditiously before yet another year of growth takes its toll on the Chesapeake and our favorite local waters.