Hempstead Lake State Park: SSAS Comments on Revised Environmental Assessment

JANUARY 2020 by Brien Weiner

On behalf of the South Shore Audubon Society, thank you for the opportunity to provide the following comments on the Finding of No Significant Impact for the revised Environmental Assessment of the Hempstead Lake State Park project that has been segmented from the Living with the Bay project in West Hempstead, New York. The South Shore Audubon Society is a local chapter of the National Audubon Society and represents approximately 1300 households in southern Nassau County. Our mission is to promote environmental education; conduct research pertaining to local bird populations, wildlife, and habitat; and preserve and restore our environment through responsible activism, for the benefit of both people and wildlife. We hold weekly bird surveys and public bird walks at Hempstead Lake State Park, and maintain a kiosk there with information about the Park’s birds. Our comments are cosigned by New York City Audubon, whose members frequently join us for bird surveys and bird walks at Hempstead Lake State Park, which is a New York State Important Bird Area (IBA).

The Hempstead Lake State Park (HLSP) project revised Environmental Assessment (EA) does not meet the requirements of a Finding of No Significant Impact. Serious deficiencies in the EA require the preparation of a full Environmental Impact Statement (EIS) and public participation in the design process to ensure the health and safety of our environment and communities.


The EA claims that DEC regulations require 1100 trees to be removed from the dams. This is questionable:

First, the regulations apply to a well-maintained dam; the inspection reports in Appendix F confirm that the HLSP dams are not well-maintained. The Hempstead Lake Dam currently shows no signs of seepage; therefore, first do no harm and leave the trees in place.

Second, vegetation is removed to prevent a root system from creating seepage paths that weaken the dam and cause it to fail. The EA states that woody material would be removed to 6 inches below ground, and stumps that would damage the stone face would be left at 4 inches above ground. These procedures still leave a root system, and one that will decompose and be more likely to create seepage paths.

Third, as stated in LKB’s 2014 dam inspection report, the Hempstead Lake Dam may be buried in a layer of soil, in which case trees would not need to be removed for inspection or repairs: It is not clear how much adverse impact impact the existing vegetation is having on the embankment. As noted previously, the original crest of the dam was narrow (approximately 24 feet). The original downstream embankment was said to be sloped at 1 vertical on 2 horizontal. For a 14 foot high dam that would have placed the original downstream toe of the dam within the current roadway pavement area. Therefore the vegetation may theoretically be outside of the original dam design limits. Additionally, the contract documents for the dam indicate that it was to be built with an impervious clay core running the full length of the dam. A clay core would force seepage flow through the dam to be much deeper than through a similar dam without a clay core, hence root capillary action has much less impact.”

Fourth, the USACE inspection report for the Hempstead Lake Dam in Appendix E recommends “larger hardwood trees should not be removed but should be inventoried and their condition monitored. If a tree dies, the area around the tree should then be monitored for possible seepage.” LKB’s 2014 report notes that removing mature trees can cause dams to fail: “Removal of multiple large trees can cause the water level through the dam to rise suddenly, destabilizing the downstream slope.” The EA should provide a detailed description of the process by which trees would be removed to prevent such destabilization.

Finally, the EA is inconsistent in its claim of following DEC guidelines, which require the mowing of tall grasses on dams: “Removal of trees on the dams could provide new habitat for Canada geese if planted with grass that is kept short through regular mowing. However, new pollinator habitat on dams would not be mowed lawns, but instead tall grasses, which are not attractive to geese” (p. 135).

The questions and inconsistencies regarding the dams highlight the need for further study of alternatives to choose the one that is best for safety and the environment.


The EA is elusive on when trees will be removed: several sections of the EA state that there will be no impact on birds because trees will be removed November 1–March 31 and several sections state that the impact on birds from tree removal will be mitigated April 1–October 31. Here are a few examples of activities that will put birds at risk:

“The November 1 to March 31 tree-clearing window for all tree-clearing activity not associated with dam improvements and bridge installation would avoid the migratory bird breeding season, which occurs between April 1 and August 31. Only tree removal associated with the dams, gatehouses and bridges component may occur from April 1 to October 31. A qualified biologist would survey trees for migratory birds prior to and during tree removal activities” (p. 171).

“Due to time constraints, trees associated with the Hempstead Lake and South Pond Dams may need to be removed outside the tree-clearing window” (p. 123).

“To avoid impacts on resident raptor species, raptor surveys would be conducted prior to and during construction by qualified OPRHP biologists to address the possible presence of raptors, including the great-horned owl. If an active nest were encountered, it would be left in place and protected until young hatch and depart, if feasible. If not feasible, the USFWS Field Office and/or NYSDEC Regional Wildlife Office would be contacted for assistance to determine the appropriate plan of action” (p. 145).

Birds will be put at risk for the following reasons:

  1. Most of the trees to be removed are on the dams (1100 of 1799 trees), therefore most of the tree removal may take place April 1–October 31 during spring and fall migration and spring and summer nesting season.
  2. HLSP is a well-known hot spot for early migrants in March.
  3. If a raptor nest is found, such as a Great Horned Owl nest, the EA does not state whether protection includes sufficient habitat around the tree with the nest. Leaving one tree, or even a few trees, will not prevent stress to the birds if they are surrounded by construction and deprived of habitat for prey and cover. Nests would be doomed to failure.

The EA is also elusive regarding the effects of tree removal for expanded trails; here is an example of two passages that occur on the same page (p. 146):

“Tree clearing to accommodate the trails would not result in the reduction and fragmentation of mature forest or loss of buffer between human activity and waterfowl/waterbirds.”

“Waterfowl and waterbird use of the NE and NW Ponds may be diminished from an increase in human disturbance related to reduced buffer distances and increased human activity along trails.”

Further, the EA claims that loss of mature upland forest will be mitigated by “increase in wetlands and water quality improvements” (Appendix A, p. 7) and “meadows that would replace woodlands” on the dams (EA, p. 122). These are false equivalencies; different habitats support different wildlife. The EA fails to account for how the loss of woodland habitat would be offset. It also fails to account for how construction activities, final design, and water level management would impact the distribution and use of the ponds by waterfowl, shorebirds, and wading birds. The impacts are especially significant in that HLSP is a designated NYS Important Bird Area (IBA) for wintering waterfowl.

Finally, the EA’s interpretation of fragmentation is questionable: the EA claims that the loss of trees will be mitigated by noncontiguous plantings around the ponds and that there will be no significant impact to birds because there are “hundreds of acres of similar habitat” available to them. There will not be hundreds of acres available when the total activity is considered: fewer trees and increased exposure and disturbance in the remaining wooded areas will limit suitable habitat. The EA also claims that tree removal could be reduced in the field, but neglects to state whether it could also increase.

A recent report in the journal Science revealed that almost 1/3 of North American birds, or 3 billion birds, have been lost since 1970; a report by the National Audubon Society determined that 2/3 are at risk of extinction from climate change (see https://www.audubon.org/- climate/survival by degrees). Habitat loss is the leading cause of their vulnerability, and it is urgent that we preserve such urban oases and IBAs as Hempstead Lake State Park to ensure their survival.


The “increase in wetlands” mentioned above and at various points in the EA doesn’t exist. The EA engages in fuzzy math and more obfuscation, referring to increases in wetlands and offsets, and at the same time admitting to a net loss of 2.76 acres of wetlands. On p. 98: “The additional emergent wetlands and open waters would offset unavoidable impacts on emergent wetlands and open water.” However, the accompanying table shows 1.76 emergent wetlands acres lost and 0.160 acres created. According to the New York State Department of Environmental Conservation, often more wetlands need to be created for those that are lost to ensure mitigation. The DEC’s Freshwater Wetlands Regulation Guidelines on Compensatory Mitigation notes that “It is very often necessary to replace more acreage than has been impacted to fully compensate for losses. Larger acreage may be needed as insurance against the uncertainties associated with trying to create a new wetland. Higher replacement ratios may also be needed to compensate for the long time it will take for a mitigation wetland to function at the same level and provide the benefits of the wetland being replaced.”

As with types of habitat in general, the EA often doesn’t distinguish between types of wetlands, and not all wetlands are suitable for all species. Further, there is no guarantee that any of the wetlands will be suitable for the birds that use them now after they are altered. Massapequa Preserve provides a cautionary example: dredging wetlands to increase streamflow resulted in the extirpation of Wilson’s Snipe and Long-billed Dowitchers from one of their only known Nassau County staging sites and in the reduction of other shorebirds.

The EA claims that loss of wetlands will be mitigated by improvement in water quality, but besides the false equivalency, that the water quality will be improved is questionable. Water quality testing for the North Ponds indicates that the existing wetlands currently provide significant water quality improvements.

The compensatory mitigation proposal in Appendix O, which the EA variously states was approved or needs approval by USACE, was released on October 11, 2019, with a 30-day public comment period that received only two comments, totaling two sentences. Neither the Citizens Advisory Committee (CAC) nor public were properly informed of its existence and a new and better publicized review period should be designated.


The Hempstead Lake Dam still does not meet DEC standards for overtopping in the revised EA: “While the likely maximum capacity of the dam under the proposed project is not expected to differ from the maximum capacity under the current, existing conditions, the proposed project would allow the Hempstead Lake Dam to withstand a modeled 39% PMP (Probable Maximum Precipitation) event without overtopping, improve the structural integrity of the dam and make the dam compliant with current dam safety requirements” (p. 44).

DEC standards require 50% PMP. Every inspection report in Appendix F highlights the inadequate spillway and need for a functioning low-level drain. For example, the DEC emphasizes the seriousness of these deficiencies in its 2018 inspection report:

“The low-level outlets are still not operable. As you are aware, the structure’s spillway does not have adequate capacity to pass the design flood for a high hazard dam. Such an event will result in the overtopping of the dam and its embankments. Since overtopping of dam embankment may result in its failure, it is important that the inadequate spillway capacity be addressed. This is a high hazard dam which means failure of this dam can result in loss of life and serious economic damage.”

The EA’s explanation that 50% PMP would put most of the Town of Hempstead underwater is carelessly dismissive; if climate change continues at its current pace, all of Long Island will be underwater within the century. The EA is inconsistent in following DEC regulations: while it claims that DEC regulations require the removal of trees from the dams, it claims that DEC regulations do not apply to overtopping.

Moreover, inspection reports in Appendix F state that the Emergency Action Plan for the Hempstead Lake Dam, in case of failure, is not up to date. Along with the inadequate spillway, this deficiency results in “the creation of a hazard to human health,” a significant impact that requires the preparation of a full EIS under the State Environmental Quality Review Act (SEQRA) [Section 617.7(c)(1)(vii)].


On p. 61, the EA indicates that the floatables catchers have a capacity for a one-year storm, which means mundane rain events. With more intense storms, which may become more frequent with climate change, the floatables catchers will be overtopped, and the floatables will flow right over the catchers. In addition, the netting will allow organic matter to pass through, but also small pieces of trash, microplastics, and toxins. The EA does not adequately consider that more could be done upstream to prevent trash from entering the watershed at its source, but allows bureaucracy to trump environmental health. GOSR needs to work with the municipalities and local high school’s district upstream. Destroying wetlands and woodlands for ineffective floatables catchers is unacceptable.


As with the wetlands mitigation, the EA employs more fuzzy math, cooking the books, with regard to soil contamination:

“Soil sample borings were collected in areas of excavation. Sampling results identified only minor instances of lead (one sample) and mercury (three samples) that exceeded their applicable Unrestricted Use/Protection of Ecological Resources Soil Cleanup Objectives... When site-wide averages were used to compare against NYSDEC Technical & Operation Guidance Series, Section 5.1.9 Thresholds, the upland soils achieved Class A Thresholds, indicating that no appreciable contamination was present” (p. 121).

In other words, contamination was removed by calculation, which doesn’t work in real life. Such negligence has real life consequences, however, when “the excavated soil would be used to construct the wetland and berms within the ponds” (p. 76).

The EA offers to avoid the problem of testing sediment samples altogether, however: “NYSDEC also indicated that OPRHP could forego further testing if all dredged sediments were disposed at an upland facility off Long Island to protect groundwater resources. OPRHP has committed to such disposal, and further testing for purposes of on-site usage of dredge material is therefore not proposed” (p. 120).

More egregious is the admitted potential of the HLSP project to contaminate the entire Mill River watershed without any mitigation plan if such an event occurs (p. 120):

“Approximately 2,473 CY of wetland cut (dredging or excavation) would be required in the NE and NW Ponds. Dredging would increase turbidity and expose nutrient-rich sediments. If disturbed, these sediments could cause the contaminants to become suspended in the water column of NE Pond, which could cause the contamination to spread to other areas of NE and NW Ponds, Hempstead Lake State Park, and farther downstream throughout the Mill River Watershed. Such disturbance presents a potential impact of exposing aquatic biota to acute toxic effects associated with potentially contaminated sediments suspended in the water column.”

The EA discusses BMPs to reduce the potential of watershed contamination, but has no emergency response plan if those practices fail. Along with the inadequate spillway and outdated emergency response plan for dam failure, watershed contamination results in “the creation of a hazard to human health,” a significant impact that requires the preparation of a full EIS under SEQRA [Section 617.7(c)(1)(vii)].


According to the EA, the greenway, trails, gateways, and waterfront access will require the removal of 41 trees and the creation of 6.73 acres of new impervious surface (p. 96–97). The greenway will be 12 feet wide and the North Ponds trails will be 6 feet wide. The Negative Declaration states, “No compensation for the loss of forest as a result of trail construction/expansion would occur.” As discussed previously in Impact on Birds, reduced buffer distance and increased human activity from the expanded trails may reduce waterfowl and waterbirds’ use of the North Ponds. The addition of lighting along the greenway is noted on p. 138, with no assessment of its impact on wildlife.

The trails are currently used by few bicyclists; the EA lacks assessment of the impact of their increased use of the park, which, in addition to disturbing wildlife, may be hazardous to pedestrians. The multiuse trails at Massapequa Preserve are a case in point, where pedestrians and bicyclists are at risk of collisions. The EA needs to consider and mitigate the habitat and safety issues of the greenway and trails. There is no proof of the EA’s claim that formalized trails will eliminate use of social trails and off-trail use of the park to reduce erosion; those who seek less exposed or frequented trails will continue to do so. Permeable or natural material should be used for the greenway, trails, and parking areas to reduce flooding and damage to habitat.

Regarding waterfront access, the EA is deficient in studying and mitigating the introduction of kayak use to Hempstead Lake when winter waterfowl are present September to April. It cannot be emphasized enough that Hempstead Lake is an IBA for wintering waterfowl in a region where both birds and suitable habitat for them are disappearing.


The proposed multimillion dollar Education Center will remove 11 trees, create 0.26 acres of impervious surface, and disturb 63,280 sf of land. Both the expense and the destruction of open space are unnecessary. The purposes of the Education Center can be achieved by repurposing an existing building; the EA does not adequately consider alternatives such as existing buildings at HLSP, Tanglewood Preserve, Bay Park, or the recently closed East Rockaway Yacht Club. According to Hempstead Town Councilman Anthony D’Esposito, the Town Board was working to issue a request for proposals for the Yacht Club “while realizing the needs of the community.”

Tanglewood, Bay Park, and the Yacht Club are arguably better locations for educational opportunities, learning spaces, community gatherings, and stimulating public stewardship over the Mill River, consistent with the LWTB objective to educate the public on stormwater and environmental management. They are more integrated into the community. Contrary to the EA’s description, HLSP is not centrally located in the Mill River watershed; HLSP lies above the floodplain. For a project called Living with the Bay, the Bay Park buildings would be directly on the bay, and provide space for activities and parking. LWTB goals strive for a holistic approach to the Mill River, while the proposed Education Center focuses on the Park. Moreover, the Center cannot provide educational programming on protecting the Park’s ecosystem when the HLSP project itself fails to do so.

As an emergency response hub, the decentralized location is even more problematic. If transportation by car is limited in an emergency, the Center will be useless to the community. A location such as Bay Park or the East Rockaway Yacht Club sits on the floodplain where an emergency response to storms and flooding is more likely to be needed, especially if LWTB is going to harden only one side of the Mill River in East Rockaway and abandon coastal marsh restoration as the EA proposes. At CAC meetings and public hearings, opposition to a new Education Center at HLSP united the community; it was seen as a colossal misuse of funds intended for Sandy victims.


GOSR is attempting to avoid the issue of segmentation by jettisoning many proposed Living with the Bay (LWTB) projects and claiming, “The LWTB Project and Resiliency Strategy are configured such that projects could advance independently, subject to availability of funding” (p. 14). The revised EA uses the same faulty reasoning as the original EA in failing to adequately consider cumulative impacts, a deficiency that was emphasized by USACE, USEPA, and USFWS in their public comments, and by HUD in correspondence obtained by a Freedom of Information Act request. For all four agencies, segmentation was a key reason why the EA did not meet the requirements of a Finding of No Significant Impact. Segmentation is also a violation of SEQRA. The revised EA includes brief descriptions of the other LWTB projects, but insufficient analysis of cumulative impacts on the watershed.

The segmentation suggests that GOSR mismanaged the LWTB projects and time is running out on the grant to complete them. In the process, GOSR eliminated the Coastal Marsh Restoration that would have been our primary defense against storm surges and was ranked #1 for prioritization in the LWTB Resiliency Strategy. GOSR is depending on projects prepared by other entities, not only OPRHP for the HLSP project, but now also Nassau County for the Long Beach Sewage Transfer, which was recently added as an LWTB project. These changes were made in violation of HUD’s requirement of CAC participation in designing and implementing LWTB; the CAC was not included in the discussion of, and objects to, these changes, which fail to meet project goals. Further, such significant changes to the LWTB plan require an Action Plan Amendment with public comment period (24 CFR 91.505).

As with the HLSP project, the Long Beach Sewage Transfer is a misuse of funds that were originally intended to mitigate flooding and create a blue-green corridor along the Mill River. And in further contradiction of the goals of LWTB, projects at Lister Park and East Rockaway High School will harden one side of the Mill River and paradoxically exacerbate flooding for residents on the other side. LWTB has been degraded in purpose and coherence.


The HLSP project meets the following criteria for an EIS under the SEQRA: will result in “a substantial adverse change in existing ground or surface water quality and quantity”; “a substantial increase in potential for erosion, flooding, leaching, or drainage problems”; “the removal or destruction of large quantities of vegetation or fauna”; “substantial interference with the movement of any resident or migratory fish or wildlife species”; “impacts on a significant habitat area”; and “creation of a hazard to human health” [Section 617.7(c)(1)(i, ii, vii)].

The proposed repairs to the Hempstead Lake Dam do not meet DEC standards for overtopping and lack an adequate spillway. Every DEC inspection report makes note of this and the resulting potential for dam failure. Further, the dam’s Emergency Action Plan is not up-to-date.

The proposed dredging in the North Ponds could disturb contaminated sediments and cause them to spread throughout the Mill River watershed. The EA does not include a mitigation plan for such contamination.

The HLSP project will result in the removal of 1799 trees and the net loss of 2.76 acres of wetlands. The destruction of habitat will have a significant impact on migratory and nesting birds in a designated New York State Important Bird Area (IBA). In addition to permanent and unmitigated loss of habitat, the EA states that tree removal may take place April 1 to October 31, during peak migration and nesting seasons, due to time constraints.

In violation of SEQRA, the HLSP project has been segmented from the LWTB project of which it is a part, and the EA lacks adequate analysis of cumulative impacts. It also lacks serious consideration of viable and comparable alternatives. The EA process has been deficient in providing basic information to the CAC and the public, and in opportunities for public participation, such as CAC meetings and public hearings. The EIS process is needed in order to provide a conversation between GOSR and the public, especially environmental justice communities, so that the project is designed to ensure the health and safety of the watershed.


The contradictions and deficiencies of the HLSP EA reveal negligence in project design that could have dire consequences for our environment and our communities. These consequences include the loss of 1799 trees, 2.76 acres of wetlands, and unique and valuable habitat for birds when 2/3 of them are at risk of extinction; and the potential for catastrophic flooding and watershed contamination. The HLSP project requires a full EIS with further assessment and public participation in order to improve the health and safety of the Mill River watershed.

Hempstead Lake State Park is one of the last and largest areas of open space in Nassau County. Its trees capture carbon and clean the air; its wetlands filter pollutants and clean the water. The North Ponds area is one of Nassau County’s last wild areas and should be preserved as such. The HLSP project, with its destruction of woodlands and wetlands, will defeat its own goals of using nature-based measures of flood mitigation and increasing access to nature by removing nature from the equation.

Thank you for considering our comments.