Environmental Factors

A Rare Habitat in New Hampshire

The Mill Pond Dam entrains an impoundment that covers approximately 24 acres and is almost a mile long and supports a diverse and rich wildlife habitat. 

 NH Fish & Game rates the majority of the Mill Pond dam impoundment and Hamel Brook as the 
Highest Ranked Wildlife Habitat in NH.

Water in the impoundment is supplied by the Oyster River extending to the west in the image.

Background of the Impoundment

The Mill Pond Impoundment extends from the dam connected to the tidal portion of the Oyster River to the entrance of Long Marsh Creek and is almost a mile long and 24 acres in area. The extended pond supports a rich diversity of wildlife that is rated by New Hampshire Fish and Game as best in New Hampshire.  

The section beyond the entrance of the Oyster River forms a channel that was excavated in the 1600’s intended to connect with the Lamprey River to provide a greater water source for the Mills by the dam.  The canal was never completed, but during periods of extensive flooding as in 2006 and 2007, the Lamprey does back up and flows into the impoundment through Long Marsh Creek.  

The impoundment provides year-round free recreational activities in terms of water sports in the summer and winter sports on the frozen pond in the winter.  It also connects to an extensive trail system off the Foss Farm Region with new access from the Faculty Neighborhood across the Kenny Rotner Bridge. The pond and upstream impoundment represents wildlife habitat; the portion beyond the Milne Sanctuary is ranked as best in NH for wildlife habitat by NH Fish and Game (see map).

The Unlikely Viability of Fish Runs in the Oyster River System  

The image to the right is the reality. During a previous drawdown, this demonstrates the volume of water that flows in Hamel Brook that could be expected with dam removal.  The resulting shallow stream will not support any fish, including juvenile herring that spend the summer in freshwater.  It will also not support any of the aquatic wildlife that currently reside in the Mill Pond Impoundment. 
Spawning fish will require consistent access to deep pools and the ability to swim up and downstream from end to end.
The UNH Dam limits water flow to the Mill Pond Impoundment

Without the Dam there will not be enough water in the Mill Pond to support any fish species.

In August and September the Oyster River below the UNH dam is a trickle providing too little water for herring, smelt and other fish species to survive. There are lots of fish currently in the Mill Pond Impoundment and the Oyster River downstream of the UNH dam.

Four species of fish migrate into the freshwater section of the Oyster River watershed during the spring.  The Sea Lamprey ( Petromyzon marinus ) migrates into freshwater to spawn inflowing sections of the river before dying. The young remain in the river for several years and filter feed before returning to the marine system to prey on other fish until adulthood.  The American Eel (Anguilla rostrata) enters freshwater as larvae (elvers) to feed until adulthood and then enter the marine system to migrate to the deep sea off Bermuda to spawn.  Alewife ( Alosa pseudoharengus ) and Blueback Herring ( Alosa aestivalis ) emigrate into freshwater to spawn and are capable of returning to the marine system to return in further years.  Alewife adults spawn in shallow vegetated areas of quiet waters in the impoundment.  Blueback Herring spawn in the running waters above Thompson Lane.  The young of both species remain in freshwater for most of the summer before migrating back to the marine system to spend a couple of years before reaching adulthood and migrating back to the Oyster River system.  

Herring species have been monitored since the installation of the Denil Fish Ladder in 1975.  American eel larvae have been also surveyed since 2014 using a modified Irish elver trap and the latest report is for 2019.  There are issues with the herring runs with proponents of dam removal claiming that this will enhance runs of herring, which is a major emphasis of the National Marine Fisheries Service of NOAA.  Increasing herring production is intended to promote restoration of ground fish stocks in the Gulf of Maine.  River herring runs have been declining in all of the river systems in the Great Bay Estuary System and there are several issues which suggest that dam removal is not going to enhance any fish species in the system.  American eel populations have been in decline all along the Eastern seaboard, but no specific cause has been identified.  Since American eels spend several years in freshwater, including the pond, it is highly unlikely that eels will benefit from dam removal.

Streamflow is reduced by water withdrawal at the UNH Water Treatment Plant during seasonal low flow (summer and fall); streamflow is stopped because of this  and the UNH impoundment falls below the spillway of the UNH dam. At a town council meeting April Talon (Town engineer) reported that streamflow was stopped 40 days during 2017. 
  • According to NH Fish and Game’s progress report from 2020, herring runs in all rivers entering Great Bay have been declining.  In the two rivers, Exeter and Winnecut, where dams have been removed the herring runs are way down:
    Exeter in 2019 – 58 
    Exeter in 2020 – 17  
    Winnecut in 2019 – 0
  • Adding a Migration Notch to the Mill Pond Dam, as was done on the Wiswall Dam on the Lamprey, could help especially in dry years when the dam upstream is not releasing any water.  The Mill Pond Impoundment supports both diverse wildlife and recreation and does serve to at least partially remove the excess nutrients that are the real issue due to town and university runoff of paved surfaces and agricultural activities.

    Address the root cause and avoid impacting the Great Bay Estuary!

  • Fish and Game closes the fish ladder after a certain period so fish cannot use the ladder to return to salt water.
  • Fish and Game has never proposed adding a migration notch to the dam to promote downstream migration of adults or juveniles.

  • The UNH Dam a little over a mile upstream is a source of drinking water for UNH and Durham and during drier periods in the summer almost no water flows over that dam and that limits flow over the Mill Pond Dam to almost nothing trapping any fish that need to leave the freshwater.

  • Dam removal would so reduce the water levels in the impoundment that no fish species could exist and would eliminate any spawning habitat for Alewife.

  • Dam removal would greatly reduce habitat for American Eel and river herring young and likely eliminate the Oyster River as habitat for these species.  


Diversity and Endangered Species 

The Mill Pond Dam impoundment covers approximately 24 acres and is almost a mile long and supports a diverse and rich wildlife habitat. 

Dam removal will so empty the impoundment that most of the aquatic species listed (see Wildlife List) with be eliminated from that portion of the Oyster River and Hammel Brook.

Species of concern are listed in the New Hampshire Fish and Game Department’s
Wildlife Action Plan from 2015.  Some of the species listed, such as Black Crappie and Banded Sunfish have not been observed/caught in the Mill Pond Impoundment or Oyster River by Harris. The only fish observed in College Brook over many years of observations was a juvenile American Eel one summer.  During that summer, a resident population of crayfish in the brook was eliminated and none has been observed since.
Reported by Dr. Gregg Moore)

Star Duckweed (Lemna trisulca) – Endangered (S1) in NH and only observed in Mill Pond
Giant Bur Weed (Sparganium eurycarpum) – Threatened (S2) in NH and in Mill Pond
Dwarf Spikesedge (Eleocharis parvula) – Threatened (S2) in NH and in Mill Pond

Northern Leopard Frog (Rana pipiens) - Listed as threatened (S3) on Wildlife Action Plan  

Seaside Brookweed ( Samolus valerandi) – Endangered (S1) in NH and just below dam.
Eastern Grasswort (Lilaeopsis chinensis) – Endangered (S1) in NH and just below dam.

The fact that efforts are being made to control invasive plants along Mill Pond Road and in the Milne Sanctuary illustrates the issue of how control is not a short term or simple problem. (These are the conspicuous ones, but there are more)

Glossy Buckthorn (Frangula alnus)
Japanese Knotweed ( Polygonum cuspidatum)
Burning Bush (Euonymus alatus)
Japanese Barberry (Berberis thunbergi)
Multiflora Rose (Rosa multiflora)
Oriental Bittersweet (Celastrus orbiculatus) 

Buckthorn Invasion

Invasive Species and Threat to Habitat with Dam Removal

Removal of the Dam will expose acres of habitat to be colonized by invasive plant species and require extensive costs both financially and in time and effort to mitigate for years.

INVASIVE PLANTS ON SHORELINE (These are the conspicuous ones, but there are more).  
These species are opportunists that grow quickly and outcompete native species and benefit from disturbed and newly exposed habitats such as will occur if the dam is removed.

Glossy Buckthorn ( Frangula alnus )
Japanese Knotweed ( Polygonum cuspidatum )
Burning Bush ( Euonymus alatus )
Japanese Barberry ( Berberis thunbergii )
Multiflora Rose ( Rosa multiflora )
Oriental Bittersweet ( Celastrus orbiculatus )

Impoundment Sediments  

Removal of the dam will release tons of sediments. Bathymetric cores show the silt contains toxic materials including heavy metals such as cadmium and chromium that will be released downstream into the Great Bay Estuary.

Image to the right from previous drawdown demonstrates  the amount of water flow of the touted "free flowing river".
Save MIll Pond Dam

Extreme Levels of Mercury in Mill Pond

Hanna Miller’s Spring 4-7-2020 Article Published in the University of New Hampshire Scholars' Repository – Inquiry Journal (Used with the permission of the Author)

Summary of Key Findings: Hanna Miller conducted field research as part of her civil engineering major in the Honors Program at the University of New Hampshire. She collected and analyzed sediment core samples from both the Sawyer Mill dams on the Bellamy River in Dover NH and the Mill Pond dam in Durham NH. The Bellamy dams, both listed as high hazard dams, were removed in 2020. Her analysis was conducted before dam removal. 

The highlights of her analysis revealed that at Sawyer Mills, Mercury levels were at most 105 ppb (parts per billion), well below the NOAA 1999 Lowest Effect Level (LEL) of 200 ppb, which describes the lowest tolerable mercury concentration for most benthic* organisms in fresh water. The analysis of the Mill Pond samples was considerably higher for Mercury, “with a peak value of 3,800 parts per billion. Several sediment samples from the Mill Pond cores contained mercury levels not only above the NOAA LEL but also above the NOAA 1999 Severe Effect Level (SEL) for mercury in fresh water, which is 2,000 ppb and describes a contamination level that causes pronounced disturbance for most freshwater benthic organisms.” 

*Benthic animals refer to organisms who live at the lowest level of a body of water.

Excerpts from the Study: 

Research, whether formal or informal, is woven into the intricacies of everyday life. In its rawest form, it is the pursuit of truth; research seeks to provide a better understanding of the world we live in. 

 The United States is home to more than 90,000 dams (ASCE, 2017). Historically, these dams have been used for navigation, irrigation, flood control, and hydropower (Bellmore et al., 2017). 

Every dam removal should include an analysis of the quantity and quality of sediment settled in the developed reservoir behind the dam—known as the dam’s impoundment—because this sediment could mobilize downstream after the dam’s removal (Evans, 2015). 

Dam removals involving contaminated impounded sediment require environmental remediation, a process in which engineers and scientists attempt to eliminate or reduce contaminants such as heavy metals (e.g., mercury), organochlorines (e.g., pesticides), and polynuclear aromatic hydrocarbons (e.g., chemicals found in coal, oil, and gasoline). Remediation is an expensive and complicated process (Major and Warner, 2008; Edwardson et al., 2016). 

The financial cost of dam removal varies from site to site; a case study published in 2016 found that the estimated cost of dam removal varied from $325,000 to $324,700,000 (Lawson, 2016). 

Insights into the quantity and quality of impounded sediment before removal are valuable to determine the volume of sediment that requires excavation, dredging, capping, or stabilization and to determine the subsequent costs of removal and remediation (Edwardson et al., 2016). However, dam removal research is severely lacking; scientists have studied the resulting water quality and hydrologic, geomorphic, and biological responses in fewer than 10% of the dams removed in the United States (Bellmore et al., 2017). 

I developed sampling strategy maps for each site. At each impoundment, I focused my samples along three transects (lines of interest) across each water body perpendicular to flow: (1) near each impoundment’s inlet, (2) mid-impoundment, and (3) downstream closer to the dam. I then selected sampling locations along the three transects in spots not previously sampled in order to complement preexisting data. 

Sediment cores from Sawyer Mill contained relatively low mercury content. The peak value from the Sawyer Mill cores was 105 parts per billion (ppb) by mass, lower than the NOAA 1999 Lowest Effect Level (LEL) of 200 ppb, which describes the lowest tolerable mercury concentration for most benthic organisms in fresh water (Buchman, M. F., 2008; NOAA, FAQs) 

Elevated mercury content levels were observed at depths greater than fifteen centimeters at Mill Pond, with a peak value of 3,800 parts per billion. Several sediment samples from the Mill Pond cores contained mercury levels not only above the NOAA LEL but also above the NOAA 1999 Severe Effect Level (SEL) for mercury in fresh water, which is 2,000 ppb and describes a contamination level that causes “pronounced disturbance” for most freshwater benthic organisms (Buchman, M. F., 2008; NOAA, FAQs).

The spatial extent of the contaminated sediment is unknown, but should the town of Durham determine that removal is the best option for Mill Pond Dam, sediment with high levels of mercury could resurface and mobilize downstream. This sediment could be hazardous to aquatic life as well as the people who fish and kayak on Oyster River. Uncovering such elevated levels of mercury in buried sediment at Mill Pond highlights the importance of understanding the quantity and quality of impounded sediment before dam removal occurs, so that steps can be taken to protect human and aquatic health. 
The 1893 Power House (now Hewitt Hall) 
Background - How the Sediments Became Polluted

The Mill Pond Impoundment has accumulated a substantial layer of sediments over the decades, which is in part normal for dammed waterways, but the rate has increased both in the pond and in the tidal portion of the Oyster River.  This is in part due to increased development but may also be due to agricultural practices that could be altered, such as the trench around Moore Fields the empties directly into the Oyster River.

The sediments in the impoundment contain high nutrient loads and organic content.  The deeper layers also contain high concentrations of toxins and heavy metals (VHB Report pages 54-64), which will create problems if they are dredged for disposal or if they are eroded due to heavy flows following dam removal.  Retaining and buttressing the dam would leave them in place, which is will avoid a negative impact on the estuary.  It is highly likely that the source of much of these toxins and heavy metals are from UNH due to past practices.    

There were two coal piles affecting College Brook. The first was by the 1893 powerhouse (what remains is now Hewitt Hall) which extended behind Hewitt Hall where the UNH bookstore used to be. This was adjacent to the train tracks laid in1841 through Durham (embankment between Hewitt and Spaulding). The second coal pile was by the second power house finished in 1929 adjacent to the present railroad tracks (moved west c.1911).    

Water Quality Impacts on Great Bay

Destruction of the Dam will actually increase pollution flowing into Great Bay Estuary.  
The Mill Pond acts as a retention pond, reducing the amount of excess fertilizer, silt, and other pollutants entering the Bay.

Destroying the Mill Pond Dam does nothing to improve the water quality of the Oyster River and College Brook. 
The pollution sources must be addressed.


Both the Oyster River and College Brook are considered impaired waterways due to high levels of nutrients from upstream sources.  College Brook originates near the UNH Dairy and then flows through the UNH campus and past the Plaza Parking Lot where there is extensive runoff from paved surfaces.  Nutrient sampling from a 2014 study of Durham Ponds showed that College Brook actually had higher levels of Phosphorus and Nitrogen than the Oyster River.

Destruction of the Dam will actually increase pollution flowing into Great Bay Estuary.

Among the root causes of the pollution not being resolved by the dam removal "solution" is runoff from impervious surfaces - like parking lots.
Below is video of parking lot snow being plowed into college brook.

College Brook Degradation & Flooding: 20 Years of Mill Plaza Violations & Deceptions,” Joshua Meyrowitz 1-4-22 (sent to PB, Con Com, and Town Council)

Water Quality Measurements

Table 2-3: 2013 mean (range) of selected water quality parameters in Mill Pond and tributaries.
DK Water Resource Consulting LLC 

More Evidence of Pollutants

In addition, in a recent interview, Dr. W. Wollheim of Natural Resources at UNH has been recorded as saying that College Brook is one of the most polluted streams in NH .

The Oyster River originates above the Lee Traffic Circle where there is extensive development.  It then flows past agricultural fields such as the UNH Moore Fields which has a trench for runoff that enters the Oyster River.  Sediment samples from the Moore Fields show elevated nutrient levels, particularly phosphates 

Provided by J. Mackie:

I took two soil samples from the UNH Moore Field on July 14 for the UNH Soil Testing Program.  

I received the UNH soil lab analysis on August 24, 2021.  The result for phosphorus is ten times the optimum range in both samples. All minerals tested, except lead, are classified as High or Very High, exceeding the optimum ranges at both sample sites.  In addition, the sample from the Flat area has higher concentrations of all minerals compared to the Hill sample (except lead).   The soil results are worse than expected; evidently the Moore Field and its drainage ditch adds significant pollution to the Oyster River. How to best use this data? I am not an engineer or a scientist…but the result speaks for itself.  If UNH will alter its practices, the phosphorus pollution causing/exacerbating eutrophic conditions during low flow in the Mill Pond can be improved.  Will the excessive amount of plant life in the shallow parts of the Mill Pond thin out or die if its phosphorus diet is reduced or removed?   UNH Cooperative Extension soil analysis is $20 per sample; I paid $40.  Quite a bit less than VHB’s estimate of many thousands/millions necessary to determine the sources polluting the Oyster River. 
The combination of high nutrient concentrations emptying into the Mill Pond combined with very low flow during the warmer and drier later portions of most summers due to withdrawal of water for UNH and Town use from the UNH Reservoir a little over a mile above the Mill Pond results in increased temperatures and lush plant growth within the pond.  However, that extensive plant growth does support wildlife and serves to remove some of the excess nutrients that would otherwise flow directly into Great Bay.

Public Comments from Town Council Meetings 

Town Council Meeting on 15 November 2021 

Jonathon Bromley

The Town Council vote for dam removal was a common sense decision based on information on a complex issue that most citizens are not informed enough about.  

Our Response: There needs to be a document that informs the voters of BOTH sides of the issue.  Set it up in question and answer format.  

Kitty Marple 
It is being done. 

Our Response: If the town is setting up an informational document with questions and explanations for citizens, then it should have input from both sides and not just be a biased propaganda tool. 

Micah Stark  

Reinforced what Bromley requested for an informational document.

Our Response: Again, the Town Council should provide both sides of the case on each issue. 

Scott Calitri 
The Town Council did the right thing and followed the data provided and inputs from organizations.  Need to educate the town about how it will be more costly to keep the dam and the environmental, recreational and historical benefits or removal far outweigh keeping the dam.  There will be no costs to letting the river run free, though does suggest restoration efforts without mentioning costs.  Trust the Town Council and the outside organizations.

Our Response: It will be more costly to remove the dam and there is both infrastructure and LCHIP funding for repairing historical dams that provide services.  It is not true that the river will run free with all the commercial and residential development and the UNH Dam a little over a mile upstream with significant water removal during dry periods.  Each major rain event, including again on December 15-16, 2021, leads to both the Oyster River and College Brook turning brown with runoff from developed surfaces that ensure the river cannot be restored to its natural precolonial system.  Dam removal will eliminate recreational activities provided by the pond and impoundment and threaten archeological sites near the dam.  Without major effort, both financial and physical, dam removal will lead to an invasives-choked minor stream similar to College Brook below the Plaza. The town and consultants provided biased information based on the desire to eliminate the dam rather than a balanced study and evaluation. 

Sean Moriarity 
So much information provided by studies and environmental groups to support dam removal and an opportunity to restore fish runs.  We should celebrate Blueback Herring.  It will be cheaper than maintaining infrastructure, but then also mentioned managing restoration which according to VHB does have a cost that was not addressed.

Our Response: The information provided was from a consulting firm paid to justify dam removal. There will actually be less habitat for Blueback Herring without the impoundment and no more spawning habitat due to the UNH Dam upstream with no fish ladder.  The problem with impaired waterways is the development above the impoundment and water withdrawal from above the UNH Dam.  Unless that is addressed, there is no restoration and only increased pollution in the Great Bay Estuary. 

Stephen  Weglarz,  oyster farmer
He is concerned about the short term impact of dam removal but then assumes things will improve over time.

Our Response: Dam removal will send toxic sediments locked in pond sediments down onto his lease sites.  There will be no improvement in water quality unless the impacts of development and agricultural practices are addressed and now the dam and pond serve to remove some of the inputs from development. 

Town Council Meeting on 22 November 2021 

Scott Calitri 
Dam repair is not possible and it will be rebuilding the dam and that will be more expensive than reported

Our Response:  One civil engineer we spoke with said that he believes it is possible to replace the load bearing plates. This would not affect the dam's historical appearance since it would be underwater.  Replacing the load bearing plates will be far less costly than removal. 

There will be no funding for repair, but funding for removal. 

Our Response: The new Infrastructure Bill has funding for dam repair.  The Mill Pond Dam is eligible for the National Register and therefore could qualify for grant funding like LCHIP.

Need to put away funds for legal costs from sickness due to toxic blooms in the pond. 

Our Response: According to Dr. Haney, a former UNH professor and expert on freshwater systems and toxic algal blooms, and the 2014 pond report, flowing water through the pond would avoid toxic algal blooms. The current dense bloom covering the pond in the summer, which has been called a scum, is actually a small plant, Star Duckweed, which is declared endangered in New Hampshire by NH Fish and Game.  It is likely that an aeration system in the pond would also help to avoid that problem.  More consistent release of water from the upstream dam needs to be done and mitigating the influx of excess nutrients impairing both the Oyster River and College Brook should be the focus. 

Town Council Meeting on 6 December 2021 

Wil Wollheim 
(His laboratory in NREN at UNH studies the impact of small reservoirs on the fluxes of nutrients into the coastal zones in New England.  He contributed to the VHB study by providing data on the Mill Pond. He is on record stating that College Brook is one of the most impaired streams in NH. )

W. Wollheim: I acknowledge that there are benefits of the reservoir – I have benefited myself. But there are also many reasons for removing the dam and restoring the river. I think the benefits of removing the dam and restoring the river outweigh those for keeping. I would like to explain why, why it is time to begin to heal the river.

Our Response (Fallacy 1): The concept of healing the river requires mitigating the causes of impairment which is nonpoint runoff from paved surfaces and nutrient overloading on lawns and agricultural fields which are the source of the impairments to the Oyster River and College Brook. Removing the dam will do nothing to solve the causes of impairment and the impaired waters go straight into Great Bay without the removal of at least some of the pollutants by the vegetation in the pond. Every time there is a significant rain event, the Oyster River and College Brook turn brown from sediment runoff, including all the chemicals washed in with the sediments, as was just demonstrated on 10 and 11 December 2021.  Dam removal will not stop that non-point runoff and there will be no healing or returning the river to its “natural state” without addressing the causes of that runoff.  

W. Wollheim:  First, the dam blocks the river herring runs causing declines in their populations.”

Our Response (Fallacy 2):  The fish ladder allows entrance to the Oyster River System, but lack of water flow and no escape notch is what impacts fish runs.  Dam removal in Exeter and on the Winnecut have resulted in very reduced runs and there will be no habitat left in the pond and rest of the impoundment to support either spawning for Alewives or habitat for the juveniles of both species which remain in freshwater through the summer.

W. Wollheim: Second, some say there is another dam blocking passage a few miles upstream so lets not remove the Mill pond dam. This is a fallacy.

Our Response (Fallacy 3): Pretending that the second dam is independent of issues in the pond and river is misrepresenting reality.  It is water removal from the UNH reservoir that limits water flow to the Mill Pond Impoundment combined with excessive nutrients in the river and brook that lead to eutrophication in late summer but there are still fish and other life in the pond and a very healthy system beyond the Milne Reserve.

W. Wollheim: Third, a concern has been raised that if the river is restored invasives will take over. That too is a fallacy. Why? First, because that is not a given.

Our Response (Fallacy 4): To suggest that it is not a given that invasives will invade the exposed areas of pond and impoundment after dam removal is to ignore reality.  Check out College Brook below the Plaza to see what the future holds.  Why are invasives being removed along Mill Pond Road and the Milne Sanctuary if there is not an issue? “But more importantly, because dams and their reservoir ecosystems are themselves invasives, invasive ecosystems rather than species, proliferating across the continent, caused by people. Creating impoundments are done for a wide range of reasons, including drinking water access and humans are only copying what beavers have been doing for many thousands of years and it is unlikely that one would label a beaver pond an invasive system.  NH Fish and Game has labeled most of the impoundment as best in NH habitat for wildlife, not to mention the ecosystem and recreational services it supplies to the surrounding community.

W. Wollheim: Fourth, the fact that the dam has historical significance, going back to original colonial settlement, has been argued as a reason for keeping the dam. But this ignores 10,000 years of prior history of the Abenaki-Pennacook people who relied on the river for sustenance.”

Our Response (Fallacy 5):  To restore the river to pre-colonial times would require removing the Lee Traffic Circle, agricultural fields, UNH and Durham as well as the UNH dam.  The river is impaired due to human development and practices and that is what must be addressed to heal the river.  But it is actually just the Mill Pond that is the target of this discussion since the Oyster River above Thompson Lane is not influenced by the Mill Pond Dam and it is impaired due to development and not the dam, though the UNH Dam certainly does influence it.  In fact, dam removal may greatly impact archeological features that date to pre-colonial times so dam removal may have a negative impact on the native people’s role in this region.

W. Wollheim: Fifth, the water quality in the reservoir is impaired because it is filling in with sediments. Removing the dam will also remove the increased water temperatures and low dissolved oxygen the accumulation of sediments in the reservoir causes. And it would allow sediments transported by the river to enter the estuary rather than settling in the reservoir, important for salt marshes to keep up with sea level rise.

Our Response (Fallacy 6): All impoundments ultimately fill with sediments, including beaver ponds, but the Mill Pond sediments include heavy metals and other toxic materials that originated from the University and Durham.  The pond serves to sequester those pollutants while continuing to provide services to the town while slowly evolving into a meadow and keeping them from Great Bay.  The tidal portion of the Oyster River has experienced heavy sediment accumulation due to all the development upstream so adding toxic sediments will do nothing to improve conditions downstream.

W. Wollheim: Sixth, some argue that the Mill Pond dam is scenic gateway to Durham. I agree it is. But, the dynamic floodplain that will replace the dam will be beautiful too, just in a different way. The recovery via ecological succession that will become evident will provide a great educational opportunity how ecosystems recover over time.

Our Response (Fallacy 7):  If there were any interest in promoting the historical and ecological benefits of the dam, pond and river, then the town has had many years to undertake such educational efforts.  Instead, the current situation points of active neglect with no educational effort by either the town or the university.  To suggest that suddenly this would happen after dam removal is a travesty.  Access to the dam is exceedingly difficult due to 108 traffic and private property abutting both sides so installing a placard is not going to do anything that could not have been done before and over the years.

W. Wollheim: Remove the dam and restore the river. All the major environmental groups in the region support this cure.

Our Response (Fallacy 8):  The issue is water quality and not the dam.  It can be repaired for far less than stated and addressing the inputs of pollutants and sediments due to development is what should be the emphasis for restoring the river.  Water flow also needs to be addressed since it is water removal from the UNH Reservoir that impacts the pond.  Healing can only occur if the causes of the problem are addressed rather than focusing on the dam to distract from the real problems.  Dam removal is a fad that is like a dogma, but it is applied in  hypocritical ways.  If dam removal is so critical, then take out both dams and while you are at it take out the Bellamy reservoir dam and all the dams on lakes around NH.  Each system is unique and while it makes sense in some situations, there are lots of positive reasons for maintaining and repairing the Mill Pond Dam and focusing instead on the sources of water impairment in the Oyster River and College Brook.

W. Wollheim: Dam removal and river restoration will be cheaper than keeping the dam, thanks to grants the town is eligible for once we vote that we the people of Durham want the cure.

Our Response (Fallacy 9):  According to Dr. Gress, the dam can be repaired for less than removal and there is funding in the Infrastructure Bill recently passed for historical dam repair.  Comments in Seacoast News article concerning Exeter River fish runs 8 December 2021.Claim for increasing fish runs on river, but quantitative sampling shows a decline at the upper dam when they were above 1-2,000/year before dam removal.  (2018 – 32 fish, 2019 – 28 fish, 2020 – 17 fish).  Why are the numbers going down if the runs are supposed to be increasing?  The article also quotes M. Dionne of NH Fish and Game that a probable cause of declining runs on the Oyster River is reduced flow during times when herring adults and juveniles are trying to exit the river.  That is due to the upstream dam and water removal for the university and town.  There has been no effort to mitigate the problem by adding a migration notch or increasing water release from the UNH Dam during periods when adult and later juvenile herring are attempting to exit the freshwater portion of the Oyster River.   

Town Council Meeting on 20 December 2021 

Councilor Tobias 
Should be putting together a fact sheet with information on the Dam issue and maybe a forum for discussion to communicate to the public.. 
Town Engineer putting together a fact sheet. 

Joshua Meyrowitz 
Showed video of Plaza illegally plowing snow into College Brook, which is against State law. 

Our Response: This has been known for many years and nothing is ever done about it.   Impervious surface (parking lots and roads) runoff is one of many negative inputs from development that impact the Oyster River, College Brook and the Mill Pond. Active neglect! 

Kathleen Blake 
(An Indigenous grandmother, former Chair and Member of the NH Commission on Native American Affairs and leader in the Indigenous Community, council woman, and spiritual leader of the Koasek Traditional Band of the Sovereign Abenaki Nation. Kathleen is the former Chair of the NH Commission on Native American Affairs, a member of the Indigenous NH Collaborative Collective, a retired science teacher and school administrator, and an alumna of UNH and PSU.  )
Referred to the Exeter River dam removal and how it has restored the river and Alewife runs.

Our Response: The Exeter river case is not representative of the Mill Pond Dam, Oyster River water source and impoundment. The Mill Pond impoundment is less than one mile downstream of the UNH dam which constrains water flow and will impede any ability for fish to spawn. Further, the Exeter dam removal reopened 21 miles of river (compared to less than ONE mile in our case) for fish runs, which have subsequently declined each of last three years from several thousand to 17 in 2020 since removal. 

Pointed out that native peoples had occupied area near the Oyster River for 12,500 years and European settlers had only arrived in 1635.  Before settlers, the river ran free and was not impaired.  Must remove dam so it can again run free and heal.

Our Response: She failed to point out that there is another dam upstream and did mention runoff from development, which are the root causes of the impairments.  Also, she suggested that fish runs would be restored, but that is highly unlikely with how little water runs in the summer due to withdrawal and how shallow the remaining drained impoundment will be.  Fish runs are impacted by not having a way for fish to leave the impoundment and negative inputs from development.  Also, she failed to mention the fact that dam removal is likely to have a negative impact on archeological sites that date to when native peoples occupied the site. 

Catherine Ashcraft
(UNH member of NREN who studies environmental policy relating to industrial heritage.)

Promotes dam removal and the fact that when people are informed about role of industrial heritage as a means to keep dams, a majority support removal.  Benefits will include ecosystem services, including fish runs and water quality.  Also suggests that alternative recreational opportunities should be developed without providing any alternatives. She qualified statements by saying some dams and made no mention of the UNH dam just upstream. Ecosystem services will decline with dam removal and nothing done to address inputs from development and water removal.  

Our Response:  Water quality will not improve without addressing runoff and fish passage will be impacted without either a migration notch or increased flow from the UNH dam.  With increasing development in town and at UNH, water withdrawals are unlikely to be increased and will likely decrease over time.