Research & Policy

Precision Conservation on Tap for Clean Water

As part of an ongoing effort to highlight the latest findings and techniques that support conservation and water protections, OSI takes a look at how LiDAR technology and other new data and tools, some developed in partnership with OSI, are changing the way we do conservation.

Conservationists seeking to implement farm restoration projects in central Pennsylvania used to cast a wide net to reach landowners with properties on the region’s many impaired streams. Not anymore. A new database ranks each of the 171,000 parcels, in three Pennsylvania counties, based on their potential to release pollution into nearby waterways. And thanks to more precise calculations, the conservationists now have a much better idea where once-forested stream buffers have been replaced with farmland and lawns, and where restoration will have the greatest impact.

The result: a more efficient and effective model for protection and restoration – with just 812 parcels targeted.  

What brought about this shift in strategy is high-resolution land cover data and LiDAR elevation data with an accuracy up to one meter instead of the previous 30 meters. The data, which has been pieced together by University of Vermont, is only available for some landscapes in the United States but is increasingly being used across the country to identify which lands to restore and protect and is reshaping the practice of conservation.

“We used to treat pollution on agricultural lands with a one-size fits all approach, but now we can tailor solutions to individual farms. As a result, we have a much better chance of focusing our work where it will have the biggest impact for keeping our waterways clean,” observes Jeff Allenby, who directs Chesapeake Conservancy’s Conservation Innovation Center.

The Conservancy, along with other groups such as the Freshwater Trust in Oregon, have been pioneering the notion of “precision conservation,” or harnessing data and new online tools to target conservation for increased impact and cost-effectiveness.

In central Pennsylvania, the Conservancy’s use of the high-resolution land cover revealed that of the 171,000 parcels, 6,300 had significant gaps in forested buffers, which can limit the effectiveness of filtering out pollutants. They further winnowed the list by requiring parcels to either be on impaired streams or have reproducing trout and to have adjacent uses that were compatible with water quality. “We basically were looking for the worst house in the best neighborhood,” says Carly Dean, a program manager with the Conservancy.

“We want to focus on restoration in watersheds that are reasonably healthy, where we can get the biggest bang for the buck. The data was key in helping us understand this.”

Not only can LiDAR and land cover data identify gaps in stream buffers or where storm water is accumulating into channels and running directly through them, the data is also being used to pinpoint the most intact watersheds that are producing clean water now and where land protection can ensure they stay that way. “Being off by 30 or 40 feet in the headwaters can be a big deal,” says Allenby.

Not only are datasets changing, but the way conservation groups interact with data is also changing. Online data tools are nearly ubiquitous in conservation initiatives.

In the Delaware River Basin Initiative, a wealth of models, including predictions of future development and assessments of the pollution caused by that development, are being combined into a single online tool that has the potential to answer many of the questions conservation groups never dreamed to be able to answer with a click of a button.

Models and tools developed by four different organizations – Shippensburg University, the Academy of Natural Science at Drexel University, University of Pennsylvania, and the Stroud Water Research Center are being combined into a single online interface that can provide conservation practitioners one stop shopping on a site called “Model My Watershed,” part of a broader suite of watershed management tools under the title Wiki Watersheds.

A team of researchers at Shippensburg University has developed a model that simulates development across the Delaware River Basin. It identifies the likelihood of conversion of a given 30-meter pixel based on repeated runs of the model. There are three scenarios, a “business as usual” scenario that assumes few changes in conservation or land development policies, a scenario that assumes that development will sprawl along existing transportation corridors, and a scenario where development is clustered around existing centers. This approach removes some of the guessing by providing a likelihood that any parcel will be developed based on many runs of the model, and allows users to consider alternative pathways of the future. Development models help inform where to place limited conservation dollars if you’re trying to reduce or redirect future development. “While we can’t know what the future will bring, looking at scenarios helps us create the future we want,” asserts Claire Jantz whose lab established the development scenarios.

The Academy of Natural Sciences has developed another model that identifies the location and quantities of the pollution load in a given stream. The “Stream Reach Assessment Tool” (or SRAT), when integrated into the Wiki platform, can also tell practitioners how much restoration would be needed to bring concentrations of key pollutants - suspended solids (TSS), nitrogen (TN) and phosphorus (TP)-  below EPA thresholds for common impairment. This helps right-size the investment. Stream networks are often long and complex.

As well, SRAT offers a land protection index, that the Open Space Institute (OSI) developed in partnership with University of Pennsylvania modeler Barry Evans, to estimate the “Ability to Protect Clean Abundant Water.” The index, which was modeled off of the national “Forest to Faucet” project, identifies watersheds that are best at producing clean water based on acres of headwaters, forested stream buffers, wetlands, and other resources that filter and clean water. For a land trust seeking to retain high quality water that hasn’t been impacted by pollution, this data helps direct where to target projects.

The SRAT tool is also unique for its ability to quickly aggregate upstream pollutant loads. The SRAT has helped practitioners think twice before implementing a restoration project or buying a parcel of land. “You have to always ask yourself, what’s upstream of my work, and are there pollutants that could degrade the water quality I’m seeking to restore or protect,” notes Scott Haag at the Academy of Natural Sciences, who innovated the computer design that allows the model to quickly aggregate upstream pollutants across a complex stream network. Answering that question used to be nearly impossible. Thanks to Haag’s work, the pollutant models can quickly summarize all upstream land uses and pollutant loads at a given location.

While getting the data to work seamlessly together keeps the modelers busy, getting conservation groups to integrate use of these tools into their day-to-day work can be equally challenging. “Practitioners are understandably skeptical at first when they see models that replace the way they used to prioritize things,” observes Chesapeake Conservancy’s Allenby. “But ultimately, if the tools deliver better conservation and lower cost, they will prove themselves.”

“The Association of New Jersey Environmental Commissions (ANJEC) has been a very reactive organization by necessity. We were always putting out fires after they started,” notes Jennifer Coffey at the ANJEC. “The water quality data in SRAT and other tools allows us to identify potential fires before they start. Now we communicate with the municipalities and can say, if you pass this ordinance or implement this stewardship practice, it will improve water quality by this much.”

Stroud Water Research Center, which leads the WikiWatershed.org® initiative, is working collaboratively across the Delaware River Basin to educate and train land trusts and others in the use of the tools. “The tools available in our Model My Watershed® online application make a very complex set of calculations very easy for the end user. So, once people are introduced to the tool, they are quick to adopt its use for their conservation and restoration planning activities,” notes Dave Arscott from Stroud.

 “The new data was a monumental foundation to our planning. When the data came out it changed the game.  I like to say it brought our loads to life,” says Michelle DiBlasio the Watershed Restoration Coordinator at the Nature Conservancy, New Jersey. “It showed us where these pollutant loads were and where they are greatest. It helped us identify where our work could really tell a story and start to make an impact at a greater scale.”

For the Open Space Institute and its Delaware Watershed Protection Fund, the new tools and data are helping to answer some age-old questions about land conservation.

“If I’m looking at a land protection project, the Shippensburg model is able to tell me the likelihood that the area will be developed if we don’t conserve the land – maybe it will become a subdivision - and Model My Watershed® can tell me if the land is indeed developed, what kind of increased pollutions loads I might expect,” adds Abigail Weinberg, OSI’s Director of Research. “Together these tools can help us either pass on projects or invest with much greater assurance that the consequences are cleaner water than we might have otherwise.”

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