Muskegon Futures: Dams & Fishes Muskegon Watershed Research Partnership Bulletin 4 Introduction Economic boon, or ecological disaster? Put ten Rogers Dam Muskegon River lovers in a room and you will un- doubtedly find takers for both of these points of view and many in between. One thing is clear, for over 150 years dams have been an integral part of the Muske- gon River ecosystem. The first major dam was built on the Muskegon main stem at Newaygo in 1854 to power a sawmill. Then came a dam at Big Rapids in 1866. The Big Rapids Dam became the river's first hydroelectric station in 1889. Next came Rogers Dam Hardy in 1906 and Croton Dam in 1907. Hardy Dam was Dam built in 1931, and last of all Reedsburg Dam near the Muskegon headwaters was built in 1940. Today Rogers, Hardy, and Croton dams lie at the heart of a sprawling hydropower operation. Together they pro- vide the regional grid with about 46,000 kilowatts of Croton Dam power, with Hardy Dam providing the majority of the generation. Despite the clear economic contributions of the hydropower dams, many people are con- cerned about their impacts on water quality and fish populations in the Muskegon River water- shed. MWRP modeling studies can provide some useful insights on both sides of the argument. The Croton Dam in Newaygo County “The facilities are li- censed to operate through 2034, at which time the structures could be re-licensed, decom- missioned and left in place, or removed from the river.” -Jeff Alexander 2005 “To those who live here, it’s alive, a part of us. The old dam... is loved by all.” Inside this issue: - Fred Mare 1982 Introduction 1 “What people cannot see, because it is buried Pros & Cons 2,3, & 4 beneath the dams, is the potential of the river.” -Paul Seelbach 2003 What Does the Fu- 4 ture Have in Store? Quoted from: The Muskegon: The Majesty And Tragedy of The Bottom Line 4 Michigan’s Rarest River , by J. Alexander (2006) Page 2 Muskegon Futures: Dams & Fishes Pros & Cons In an age of rising atmospheric carbon dioxide levels and increasing energy costs, emission-free electrical gen- Rogers, Hardy, and Croton Dams do indeed function like eration is a valuable asset. While dams supply only a minor large load traps on the Muskegon River. Nitrogen, phospho- amount of the state’s need, they are important in the overall rus (a key plant nutrient), and sediment load are all signifi- operation of Michigan’s electric grid. And the scenic quali- cantly reduced as the river passes through them. Our mod- ties of energy-producing dams on the Muskegon River pro- els suggest, for example, that Croton Pond removes more vide an iconic contrast to coal and gas fired plants that than eight tons of phosphorous (as TP: Total Phosphorous) somehow seem part of a passing age. The backwaters of from the Muskegon River each year and stores it in reser- the impoundments have their advantages too. Beautiful voir bottom sediments. The capture of nutrients and sedi- lake-like frontage on all three impoundments provide a rec- ment in the reservoir helps keep the river’s most productive reational mecca for many. Providing fishing, skiing, swim- salmon and steelhead spawning grounds (above Newaygo) ming, and boating opportunities, these impoundments relatively free from fine sediments and algal accumulations. themselves figure large in the economy and hearts of many This filtering of the Muskegon River would be lost if the local residents. large dams were removed (see FIG. 1). But are there benefits to the rest of the river ecosystem, Finally, as often correctly pointed out by dam advocates, and not just to people? Yes there are. Many rivers have the reservoirs help natural in-line lakes and impoundments. Lakes and reser- keep most of the voirs function as a kind of trap for sediments and especially upper river system for dissolved nutrients that are routinely transported down- free from parasitic stream by rivers. Reservoirs can enhance the “self clean- sea lamprey. Like- sing” aspect of river function in the sense that they remove wise, it restricts and store (at least temporarily) material loads in transport. the upstream Water enters a reservoir carrying sediment and nutrients. movement of other When that water falls over the spillway it has left much of invasive species its “load” behind. As a result the river reach downstream like the round goby sees “cleaner” water, and the nutrients and sediment left which is currently behind having become trapped in the local reservoir eco- spreading up the system. The amount of sediment being carried by a river as river from Lake it exits an impoundment is very small indeed. That water is Michigan. On the said to be “hungry” for sediment and it erodes smaller ma- other hand the terial like sand from the riverbed below a dam leaving be- reservoirs have hind coarser gravels and cobbles. become a source MWRP modeling and measurements make it clear that for zebra mussel invasion of the main stem river. FIGURE 1. Modeled affect of the re- TABLE 1. Physical characteristics of the Rogers, Hardy, and Croton impoundments. moval of the three mains tem hydropower dams on average material and water loads to the lower Muskegon River. Impoundment Characteristics Rogers Hardy Croton N load_g/day is total inorganic nitrogen load; P load_g/day is total phosphorus Location (River Miles above mouth) 83.7 58.7 52.8 load; Erosion potential is change in domi- Drainage Area (sq. mi.) ~1,746 ~1,851 ~2,224 nant discharge rate; Sed load_g/day is Max. Surface Area (acres) 449 3,902 1,209 total (suspended +bed load) sediment load; Sed_ppm is average sediment Max. Surface Level (feet above sea level) 861.6 822.5 722.0 concentration; Q50 is the long-term me- Gross Storage Capacity (acre-feet) 4,678 134,973 21,932 dian discharge; Q95 is the long-term 95% exceedance flow (a low flow); Q05 is the Target Surface Level (feet above sea level) 861.3 822.0 722.0 5% exceedance flow (approaching a Mean Depth (feet) 10.4 34.5 18.1 storm flow); all discharge estimates were based on the MREMS standard 1985- Normal Usable Storage Capacity (acre- 300/0.7 5,007/1.3 1,181/1.0 2005 climate model. feet) / Impoundment Fluctuation (feet) Normal Impoundment Fluctuation (feet) 0.7 1.0 1.0 Drawdown (feet.) : dewatered acres (% 0.5 : 51 1.0 : 57 N/A surface area) (1.3%) (4.7%) Average Annual Flow (cfs) 1,344 1,460 1,871 Impoundment Retention Time (days) @ 1.8 46.6 5.9 Avg. Annual Flow1 Muskegon Watershed Research Partnership Page 3 Pros & Cons (continued) The issue of restricting movement Interestingly, the modeling also predicts upstream, of course, “cuts both ways”. small increases in smallmouth bass A common argument against main habitat (up 3%) as some downstream stem dams is that they ecologically wetland areas become cooler. On the fragment the river system. This means Pike & basstrout other hand northern pike and the trout that beneficial as well as deleterious all lose very small amounts of habitat fish movements are severely re- below Croton Dam. Most of these minor stricted. And that recruitment of river GL walleyecoho differences arise from increased flows spawning species from Lake Michigan in the wetlands of the Fish and Game is much reduced from what it could be. chinook Area, which affect water temperatures This includes Lake Michigan spawning on small valley tributaries. -100 0 +100 +200 +300 salmonids like steelhead, coho steelhead The complexity of the models’ re- salmon, and chinook salmon, as well Effect of Dam Removal sponse to a dam removal scenario is a as Lake Michigan and Muskegon Lake [% change in useable habitat] good reminder of the many important populations of walleye. The same ap- indirect (and often unexpected) linkages plies for other river spawning species that occur in river ecosystems. The FIGURE 2. MREMS estimates of the like the endangered lake sturgeon, MREMS modeling highlighted and/or percent increase in useable habitat for key several species of suckers (notably the sport fish of the lower Muskegon River. confirmed some other important impacts white sucker and the redhorses),. Pike and bass = smallmouth bass and of the existing system of dams: (1) wa- northern pike; trout = brook, rainbow, and ter temperatures below Croton Dam are An MREMS “dams removed” sce- brown trout; GL walleye = walleye returning warmer in the summer and fall, and nario modeling supported the conten- to Lakes Michigan or Muskegon; chinook = colder in the late winter and spring than tion that large areas of useful habitat chinook salmon; coho = coho salmon; they would be without the dams; and (2) would become available (FIGS. 2 and steelhead = Lake Michigan run steelhead. the hydrologic models suggest (and 3) if the three hydropower dams were empirical water balance studies con- absent. Steelhead and walleye in particular would have firm), that flows below Croton Dam are slightly reduced by more than triple the current levels of useable habitat (a evaporation in the reservoirs, and because the impounded greater than 200% increase). Coho and chinook salmon waters reduce valley groundwater upwelling. The magni- habitat increased as well by 44% and 88%, respectively. FIGURE 3. Model simulations of currently available adult habitat, and of habitat that would be made available if Croton, Hardy, and Rogers Dams were % of Muskegon River miles with suitable habitat dams: 2% dams: 4% dams: 11% no dams: 7% no dams: 7% no dams: 33% GL walleye chinook steelhead Muskegon Watershed Research Partnership Page 4 Pros & Cons (continued) tude of the overall impact of these changes on the lower Muskegon River ecosystem is difficult to assess.