Stream Smart Road Crossings & Maine Barrier Surveys Alex Abbott Welcome! GIS Analyst & Restoration Specialist Under Contract to: Gulf of Maine Coastal Program U.S. Fish and Wildlife Service Welcome! Thanks for taking the time to join us today. 1
Stream Smart Crossings… Maintain fish and wildlife habitat while protecting roads and public safety. Stream-smart crossings maintain fish and wildlife habitat while protecting roads and public safety. They also help us be prepared for the large and frequent storm events that have been washing out roads around the state and the northeast in recent years. Ask, “What values are most important to you?”
Free-flowing streams are valuable Because they support our world class fisheries. Fishing is the most popular outdoor sport in Maine, with over 260,000 recreational anglers. This generates significant economic benefits: $100 million in wages and salaries $200 million in retail sales $20 million in tax revenues Stream fishing is an important mainstay in many rural economies throughout the state. Over 50 native fish benefit from the increased stream access and improved habitat that stream-smart crossings provide. Healthy streams also greatly reduce flood damage and associated costs not reflected in the benefits just mentioned. 3
Brook Trout Though we’ve got more intact populations than elsewhere, our habitat is impaired, too. Again, green on the map represents areas with intact brook trout populations, spread over a good portion of the state. Red represents impaired brook trout habitat. One of the contributing factors in degrading these red areas is the lack of stream-smart crossings.
Fish need to move Deep Water Cold Water Refuge Refuge Spawning Habitat Foraging Areas Nursery Habitat Seasonal Habitats So why do fish need free-flowing streams? Because they need to move. So connected streams are critical! Fish need to move because they cannot find everything they need to survive and reproduce in one location. They need large connected areas of HABITAT, or “living space”. This habitat needs to have essential elements for fish to thrive, and fish need to have access to enough of it and if it is blocked or fragmented, or otherwise limited, fish suffer. One analogy is to think about a small fish tank where fish can only get so big because of the space available to them. This is similar to fragmented stream habitat; when fish are not able to reach essential habitat fish health can suffer, and can even changes them genetically (i.e., selecting for small fish). Movement is important for: Daily feeding, shelter and resting Seasonal and other changes in habitat conditions, like during low flows in summer, and with ice in winter Reproduction – finding suitable spawning areas Dispersal to find suitable nursery habitat Overall - access to a variety of habitats: spawning, nursery, foraging, deep water, cold water refuge 5
As an example, Atlantic salmon parr and young brook trout are often found miles from where they were born: 3-5 miles for salmon parr; adult trout will often move 12 miles if able. 5
It’s not just fish Photo: NH Public TV But free-flowing streams don’t just benefit fish. They benefit everything that supports the fish, from insects to microorganisms. They benefit everything that relies on streams, whether they live there or just stop by for a meal. Freshwater mussels filter water and provide food for other things, including species that live on land or come to streams occasionally. Many species thought of as terrestrial, or land-dwelling use stream channels, riparian areas or floodplains. Stream channels are important corridors for animals such as mink and otter, salamanders and turtles. Without stream-smart crossings, such animals are often forced to travel by crossing roads, with unfortunate consequences.
And…Altered Stream Processes It’s also what the stream does Regulates the flow of water What else does a free flowing stream do aside from offering habitat for fish and wildlife? It regulates the timing and duration of stream flow in a way that supports fish and wildlife, and also helps people because it stores flood waters.
Altered Stream Processes Moves organisms and material Free-flowing streams transport material that creates and maintains habitat for fish and wildlife, including a continual supply of nutrients and insects, food for many of them, and woody debris, and sediment. This material creates places for wildlife to rest, feed, and spawn, and supports the health of the stream.
Altered Stream Processes Maintains water temperature Free flowing streams allow for natural temperature variations that fish and wildlife are adapted to deal with.
Small streams are essential. They make up a large percentage of stream miles Cumulatively providing more habitat than large rivers Provide important spawning and nursery habitat for fish. Smaller streams have higher densities of juvenile Atlantic Salmon and Brook Trout Support species not found in larger streams and rivers 10
OK, so free-flowing streams are valuable. What’s the problem? Barriers! Road crossing culverts are the major barrier fragmenting stream habitat. With a design life of 30+ years, culverts can be fairly long-term barriers. But they don’t have to be. While culverts have traditionally been intended only to pass water, without causing problems for the road, It’s only recently that we’ve begun to understand how they need to be designed in order to work with the stream. Now stream-smart designs can meet our transportation needs w hile allowing the stream to flow freely. 11
HOW do culverts block fish passage? A) Flow too fast A B C – Undersized or Too Steep B) Flow too shallow – Set too high C) Physical barrier – Outlet free fall – Inlet Blocked – Thermal Barrier Essentially there are three ways culverts block fish passage. Often there is a combination of passage problems at a site. 12
Flow too fast When a culvert is too small for a stream, the water flows faster. The culvert acts like a funnel, with the upstream water held back as in the wide part of a funnel, and the flow through the culvert is much faster like the liquid coming out of a funnel. Even if a fish was able to get into a culvert like this, there is a good chance that it would be too exhausted to travel the whole length of the culvert without any chances to rest. And to top it off, in this culvert, the fish would also have to be able to jump up into it. 13
Flow too shallow At first glance it looks like this culvert is way over-sized, but only because this view is of low summer flows. During higher flows, for example in the spring and fall, this culvert may not be a fish barrier. However, during the summer months in low flow conditions when fish are seeking cold water refuge upstream or need to move for other reasons, this culvert is a fish barrier. 14
Physical barrier: Outlet free fall Perched culverts are another example of how an improperly installed culvert reduces stream passage. This picture represents a severe case, but perched culverts are extremely common. 15
Physical barrier: Inlet blocked Culvert Another extremely common result of undersized culverts is debris blocking their inlets. The smaller the pipe, the more likely to clog. Frequent maintenance is needed to avoid road washouts and culvert failures.
Tidal restrictions: Shrinking wetlands In addition to everything we just talked about, barriers on tidal streams can have dramatic habitat impacts And the impacts are… Reduced wetland acreage, smaller salt marshes Whether they are perched or simply undersized, road crossings on tidal streams can often restrict the amount of water reaching upstream wetlands during the flood tide, which means fewer acres are wet during the average high tide and the marsh shrinks. On salt marshes, a lack of tidal flushing creates conditions favored by invasive species like the common reed, which can take over and limit habitat for the salt marsh fish and wildlife that used to live there.
Since 2007, many partners in Maine have conducted surveys to identify and rate crossings across the state, providing us with lots of data to set priorities for restoration – over 20,000 records. Maine has assessed more of its stream crossings proportionally than any other state in the nation, and while this data is not complete, it provides very valuable information.
Culverts are often barriers All Crossings: Culverts Only: n = 16,525 n = 12,270 Maine field surveys over the past few years show that most road crossings with culverts act like thousands of dams across the state. 40% are barriers and another 40-50% may be barriers at certain times of the year or for some species and ages groups of fish, and are certainly barriers to the healthy free flow of their streams.
The problem is widespread Within a part of the watersheds of southern Maine shown here are at least 700 barriers due to problem culverts. Barriers prevent or limit upstream access, so an average of 25-40% of stream miles are blocked to fish and other organisms. 20
Maine Stream Habitat Viewer I’d like to run through just a few features of the Viewer so you get a sense of how it’s information can be used… Here I’ve selected my geographic area of interest using the Search tool and we’re now looking at the town of Cushing on Maine’s Mid-Coast. 21
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