River Restoration and Dam Removal River Restoration and Dam Removal in North Carolina in North Carolina Lynnette Batt Associate Director NC River Restoration Program
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River Restoration and Dam Removal River Restoration and Dam Removal in North Carolinain North Carolina
Lynnette Batt Associate Director
NC River Restoration Program
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American Rivers is a national nonprofit dedicated to the protecting and restoring rivers for the benefit of both people and nature. River restoration/dam removal is one of our four main program areas. HQ out of DC, with regional and field offices around the country, including Lynnette’s office in Durham, NC.
Dams in US79,000 in NID Database
2.5 million -
NRCS estimate, inc. ponds
High Hazard
Significant Hazard
Low Hazard
Hazard Classifications:
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Map of National Inventory of Dams, a database maintained by the Army Corps of Engineers About 80,000 dams on this database; includes >25 ft w/ 15ac-ft capacity or >6ft w/ 50ac-ft capacity About 2.5 million small pond dams had been constructed by the NRCS as of 1977 as part of their watershed management approach
Dams in NCDams in NC
5,600 in NC Dam Safety Database
60,000 to 80,000 estimate by NCDWR, includes farm ponds
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Map of the dams in NC, created from an inventory maintained by the NC State Dam Safety Program The Dam Safety program regulates dams 15 feet high AND with 10 acre feet of impoundment, and those that are considered “high hazard” (meaning that if they failed they could endanger life or property downstream) Majority (close to 90%) of dams in NC are privately owned Many were built decades ago to power mills which have since shut down Less than half are serving any functional purpose like water supply, hydropower, irrigation, flood control, etc
Dams in SC
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Very similar story for SC But in SC, there is almost no active regulation by the state
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Aging dams create a market for removal Almost 900 dams have been removed in the United States over the last 50 years (American Rivers) Design life often 50 years; can last longer, many 100 years or more; but eventually, esp w/out maintenance, they will fail When this happens, you have no control over sediment, flooding, etc
Dam Removals in NCDam Removals in NCNameName StreamStream BasinBasin DateDate
AltapassAltapass DamDam Roses CreekRoses Creek French BroadFrench Broad 20102010
Buckhorn DamBuckhorn Dam Buckhorn CreekBuckhorn Creek Cape FearCape Fear 20102010
Dillsboro DamDillsboro Dam TuckaseegeeTuckaseegee RiverRiver Little TNLittle TN 20102010
SteelesSteeles Mill DamMill Dam Hitchcock CreekHitchcock Creek Pee DeePee Dee 20092009
Spruce Pine DamSpruce Pine Dam North Toe RiverNorth Toe River French BroadFrench Broad 20092009
Pleasant Green DamPleasant Green Dam EnoEno RiverRiver NeuseNeuse 20072007
CarbontonCarbonton DamDam Deep RiverDeep River Cape FearCape Fear 20062006
Lowell DamLowell Dam Little RiverLittle River NeuseNeuse 20052005
Freedom Park DamFreedom Park Dam Little Sugar CreekLittle Sugar Creek CatawbaCatawba 20022002
Unnamed DamUnnamed Dam Marks CreekMarks Creek NeuseNeuse 20022002
Rains Mill DamRains Mill Dam Neuse RiverNeuse River NeuseNeuse 19991999
Quaker Neck DamQuaker Neck Dam Neuse RiverNeuse River NeuseNeuse 19981998
Cherry Hospital DamCherry Hospital Dam Neuse RiverNeuse River NeuseNeuse 19981998
Ash Bear Pen DamAsh Bear Pen Dam UnknownUnknown UnknownUnknown 19901990
FornyForny Ridge DamRidge Dam UnknownUnknown UnknownUnknown 19881988
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Dam removal is not new in NC – we’ve done many great projects This is only a partial list of the higher profile projects, probably twice this many at least NC does have guidance for doing dam removal as compensatory mitigation for stream impacts– see shared folder online for this document NC Dam Removal Task Force – now the NC Aquatic Connectivity Team – group of state and federal agency folks working together to identify and pursue dam removals and other aquatic barrier removals like culvert replacements
YouYou’’d like to manage a projectd like to manage a project
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Goals for NC and SC: remove 25 dams a year Other states are doing this, like Pennsylvannia – this photo shows a group of agency and nonprofit folks in PA taking a dam down the old fashioned way… note man in front with the sledgehammer – this is the person in charge of permitting for PA dam removals To meet this goal, we need more momentum and capacity In particular, we need people to recognize that dam removal is one of the fastest, most cost effective things we can be doing to restore both streams and rivers We also need people to manage projects: identify opportunities, bring partners together, assess feasibility/constraints, find funding, and hire and oversee consultants – Brian Graber will discuss the project process in greater detail Best project managers are from nonprofits and state fisheries or environmental agencies
LoticLotic, free, free--flowing riverflowing river
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What are the impacts of a dam, and, therefore, the benefits of removal? The following set of graphics will walk through this We start with a free-flowing river, also known as a lotic system; native fish, mussels and other aquatic species move freely and benefit from diverse and healthy river habitat
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Free-flowing, dynamic stream, achieving all the multiple functions of a stream
When you build a dam, the first, most immediate impact is a change in the hydrologic regime of the river, and often times reduced flow downstream
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Brian Graber at a site with major flow issues
DAM!
Blocks migration and Blocks migration and connectivityconnectivity
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Concern for both migratory, or anadromous species, as well as resident species and their local migrations Fragmenting populations of species can also have long-term genetic impacts
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As soon as the dam is removed, these species are able to migrate freely again Many anadromous species, such as American shad (lower left) migrate hundreds of miles inland to spawn; same with American eel (top left); Hickory shad (top right) and sturgeon (bottom right) are also common migratory species in the Southeast
Traps sediment, Traps sediment, blocks transportblocks transport
DAM!
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Sediment quickly accumulates behind a dam and depending on flow and type of sediment, can actually fill in the reservoir In NC this often leaves a silt/clay bottom, which is not good habitat for most river-going species
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Rivers are meant to transport sediment. Bedload material like cobble and gravel can be particularly important to a diverse stream habitat. When a dam is removed, this transport process is restored, and sediment-starved sections downstream of the dam will be replenished. Depending on type, quantity and quality of sediment, its management during removal can be an important consideration; Laura Wildman and Sara Ward will discuss this in more detail
Water quality impacts: temp, Water quality impacts: temp, DO, TSS, DO, TSS, eutrophicationeutrophication
DAM!HOT!
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Because nutrient-carrying water is slowed in an impoundment, algae blooms and eutrophication are common. Both the slower/deeper water and eutrophication can lead to significant decreases in DO. Finally, the slower/deeper water can develop thermal stratification in which the top water layer heats up –this is what spills over the top, thereby increasing the water temperature downstream Removing the dam will flush nutrients through the system and a provide better connection to the floodplain downstream where nutrients can be filtered out of the water Flowing water is also less conducive to algal growth, and will have higher DO and a more appropriate temperature regime
Sediment in Jordan Lake (these are kayakers)
Algae blooms in Falls Lake
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Two of our most notable reservoirs nearby, and the water quality issues they have…
The change in habitat behind a dam from a free-flowing river, or lotic system, to a slow-moving impoundment, or lentic system, is not supportive of many species of freshwater fish and mussels. Therefore we often find both fewer species and decreased abundance of species behind dams
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Complex, messy habitat – root wads, leaf packs, other woody debris, boulder, cobbles – is natural in a free-flowing, undisturbed stream. This provides a refuge for a diversity of native species and all stages of their life history
Photo by Tim Watts
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The SE region is home to nearby 2/3 of the freshwater fish and over 90% of the freshwater mussels in all of North America. We need all the intact, high quality habitat that we can get. From left to right: Carolina redhorse, mussel surveys on the Uwharrie River, Cape Fear shiner, Snail bullhead, Neuse River waterdog One dam isn’t so bad. But consider the cumulative impact of thousands.
Impacts to recreationImpacts to recreationDAM!DAM!
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Not exactly the kind of fishing many are going for… Lowhead dams can be hidden in high flow and create very dangerous hydraulics Even when visible, they require portage
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More, bigger and better fish in free-flowing streams and rivers Happy, safe paddlers, swimmers and hikers. A blue trail can connect a community back to their river.
Economics, safety Economics, safety and liabilityand liability
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Dams seem permanent, but over time they wear until eventually… they fail The landowner is responsible for their upkeep and liable for their failure and damage caused Most dams in NC are small, outdated, and no longer maintained, and we’re seeing failures regularly (think Hope Mills… and that was a new one!) The cost of repair has been found to be, on average, 3 times more expensive than the cost of removal – and that’s a one time cost!
Photo by Mary Chind, Des Moines Register
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For a dam removal to move forward, you first have to have a willing owner Safety, economic and liability issues are often the driving forces that get that willing owner – while the owner and the public might care about fish, bugs, etc, but this rarely drives their decision Even small, run of river, lowhead dams pose significant danger in certain flow conditions due to the hydraulics Lower right: 2010 Pulitzer Prize winning photo – construction worker rescuing a woman who went over the Center Street Dam in Des Moines with her husband in a boat Lower left: Ka Loko Dam breached in 2006 and killed 7 people. Owner is being tried for 7 counts of manslaughter and reckless endangerment. “Historically, courts have sought to compensate those injured by a dam failure.” - ASDSO
Lowell Mill Dam, Little River: Before Removal
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Here is a series of before/after pictures of a few dam removals in NC to give you an idea of what we’re talking about. These show how quickly the river can restore itself by simply getting the dam out. Most of these projects will be covered in more detail in the “Ecological Success Stories” section of the workshop.
Lowell Mill Dam, Little River: 3 Years After Removal
Dillsboro Dam, Tuckaseegee River: 2 mo. after removal
Buckhorn Dam, Buckhorn Creek: Before removal
Buckhorn Dam, Buckhorn Creek: 1 mo after removal
Steeles Mill Dam, Hitchcock Creek: Before Removal
Steeles
Mill Dam, During Removal (July, 2009)
Steeles
Mill Dam: 2 mo after removal
Questions?Questions?
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Summary: How can we remove 25-30 dams/year in NC and SC? need momentum and additional successful demonstration projects need to recognize that dam removal is one of the fastest, most cost effective things we can be doing to restore streams and rivers need people to manage projects: identify opportunities, bring partners together, assess feasibility/constraints, find funding, and hire and oversee consultants need improved funding sources at the state level – mitigation? need strong support from dam safety program
