Lower SusquehannaFISHING CREEK RD

Drumore D R Township E DG RI Y ON RM H A B A L D E A G L E R D

D R L HIL E AT L S

RD OM OTT PEA CH B (Limit of Aerial imagery)

Peach Bottom Township

R IV E R (Limit of Aerial imagery) Aerial of (Limit V IE W R D

D N R ATIO ST ES IN HA

Fulton Township

RD ING D YORK N LANCASTER LA KS COUNTY COUNTY COO Lancaster County Natural Heritage Inventory Update 2008 Legend Species of concern core habitat Natural Heritage Area Roads Supporting Landscape PA Turnpike Streams All other roads Riparian Buffer Municipal Boundary

Miles 0 0.5 1 2 Lower Lower Susquehanna River – Notable significance

PNHP Rank1 State Last Observed Species of Concern: Quality2 Global State Status1 (y-m-d)

Plants: Sensitive species of concern 3 - - - 2000-07-12 C

Animals: Osprey (Pandion haliaetus) G5 S2B PT 2004-06-07 E

1 Please refer to Appendix IV for an explanation of PNHP ranks and legal status 2 Please refer to Appendix V for an explanation of quality ranks 3 This species is not named at the request of the agency overseeing its protection

Location: This Natural Heritage Area includes the section of the Susquehanna River south of the Conowingo Islands below the Holtwood to the / Maryland border. o Municipalities: o Drumore Township, (Lancaster County) o Fulton Township, (Lancaster County) o Peach Bottom Township, (York County) o Cecil & Harford Counties, Maryland o USGS Quadrangles: o Conowingo Dam Quadrangle o Delta Quadrangle o Holtwood Quadrangle o Wakefield Quadrangle o 1990 Lancaster Natural Areas Inventory reference: o “SA592” (Holtwood Quadrangle)

Description: This Natural Heritage Area does not include the cluster of islands and bedrock outcrops just south of the , but instead focuses on the flat water area between the Conowingo Dam in Maryland and the first dam on the Susquehanna River in Pennsylvania at Holtwood, referred to as Conowingo Reservoir. The slow, open water is popular for recreational boating activities. This portion of the river has only a few small islands that remain after the flooding of this portion of the river by the construction of the Conowingo Dam in Maryland. The upland shoreline on both sides of the river within 300 meters of the river’s floodplain is included within this area.

Species of Concern Considerations: Plants: o The sensitive plant species at this location typically grows on dry, open, rocky ground, such as on shale barrens, slopes, and cliffs. Occurrences of this species and its habitat are threatened by human-related habitat loss, natural succession, invasive species, quarrying, and the collection of wild plants by gardeners. Because of the preference of the species for sunny conditions, active management – such as fire or invasive species removal - may be required to maintain the proper successional stage and ecological conditions. Animals: o The man-made lake on the Susquehanna River formed by the Conowingo Dam provides habitat for a nesting pair of Ospreys. These birds adapt readily to human activity and often construct nests on man-made structures (Brauning 1992). Being primarily fish eaters, Ospreys utilize aquatic habitats for food gathering and upland habitats or prominent features as nesting areas.

363 Lower Susquehanna River

The forested edge of the river and the large body of flat water are both important components of the Osprey’s habitat preferences.

Forest Cover / Natural Communities: The plant community types depicted are only approximations delineated from 2005 aerial photography interpretation and were followed up with minimal selective ground-truthing. Community types follow “Terrestrial & Palustrine Plant Communities of Pennsylvania” (Fike 1999) where appropriate, and describe general land cover types where they are not (*). o Most of this Natural Heritage Area is the open water of the Susquehanna River, but is also includes the forested slopes adjacent to the river. The natural communities delineated for this area include: o Hemlock-tuliptree-birch forest o Tuliptree-beech-maple forest o Red oak-mixed hardwood forest o Dry oak-heath forest o modified successional forest* o shrubland* o Areas identified as modified successional forest are considered an early stage of recovery from disturbance from past agricultural activity, repeated logging or other intensive land uses. In time, these areas can return to more mature conditions. The process of natural succession can be assisted by invasive species removal, selective removal of early successional trees and reducing deer populations to allow native trees to grow above the browse line. Forest restoration efforts should strive to mimic nearby high quality natural communities in a similar topographic and hydrologic position.

Ownership: o Norfolk Southern Rail Corp owns an active railroad rights-of-way along the eastern shore of the river. o Lancaster County Conservancy owns the adjacent Ferncliff o PECO Energy Corp / owns Mount Johnson Island, the only sizable island in this portion of the river, much of the uplands adjacent to the river and utility rights-of-way leading east and west across the river. o Except for the residential lots associated with the towns of Peach Bottom and Fishing Creek, most of the area on the Lancaster County side of the river is held in relatively large parcel size.

Habitat Disturbances: o Historic – o Water quality of the river was severely degraded by direct pollution from sewage, industry, mining, agriculture and was exacerbated by the removal of most of the forest canopy within the upstream watershed at the turn of the century. o Conowingo Dam was built across the Susquehanna River in the 1930s for electric power generation forming what is referred to as Conowingo Reservoir. The construction of the dam has resulted in the long-term flooding of the original riverine habitat. This large, nearly still portion of the river significantly differs from the original hydrology of the river that was much more influenced by the natural disturbances of seasonal flooding and ice scour. A number of islands and bedrock outcrops were permanently flooded as water backed up behind the dam. The original shoreline of the river was also permanently flooded. This modification of the river environment likely permanently flooded seasonally shallow water habitats that would likely have supported plants and animals in similar habitats potentially including species of concern. Much of the silt and other particulates transported by erosion in the Susquehanna River watershed settle to the riverbed as the swifter river water enters the slow waters of Conowingo Reservoir. This deposition of material will eventually fill all the space behind the dam.

364 Lower Susquehanna River

o The construction of many smaller on the Susquehanna River and its tributaries in the early 1800s severely reduced the American shad and other anadromous and catadromous fish from much of their traditional spawning streams. Many dams were breached in the late 1800s and the shad migration temporarily resumed. The construction of the series of four large hydroelectric dams on the Susquehanna River between 1904 and 1932 eliminated the American shad from the upper reaches of the Susquehanna almost to the close of the 20th century. Fish trap and transport programs implemented during the 1970s moved fish upriver by trucks in an effort to bolster shad populations. Improved fish ladders were constructed on the Conowingo, Holtwood, Safe Harbor and York Haven dams in the 1990s to reopen the upper Susquehanna River for shad spawning. o With the elimination of anadromous and catadromous fishes from much of their historic range in the Susquehanna watershed, several species of freshwater mussels, which depend on suitable fish hosts for a portion of their lifecycle, also experienced declines. The total range of fish hosts for several mussel species is clearly understood, but recent studies indicate that the American eel may have been an important host for several mussel species. Since the eel is eliminated from much of the Susquehanna River, this may have led to considerable declines in native mussel populations. o The railroad was built along the east shore of the Susquehanna River. o The native forests were replaced by agricultural fields on much of the flat terraces overlooking the Susquehanna River. Active agricultural fields crowd the slopes of the Susquehanna River in several places. o Current – o The Peach Bottom electric generating facility was built along the western shore of the river. Water heated to produce steam for electric generation is returned back into the river, raising the local temperature of the surrounding river water. o Powerline corridors were cut though the upland forests and transmission towers were built in the river on Mount Johnson Island and on the adjacent shoreline slopes. o The railroad along the Susquehanna shoreline impedes animal movement from the river to the uplands and visa versa, especially for small animals like amphibians, reptiles and small mammals that may consider the railroad an insurmountable obstacle. o The four hydroelectric dams on the Susquehanna River present the major obstacle to anadromous and catadromous fish migration. Recently installed fish ladders have improved the condition for anadromous fishes, but catadromous fishes continue to be excluded from most of the Susquehanna River watershed. o Residential development has increased along both sides of the river including the floodplain of the river and on the slopes overlooking the river. o Garden debris and other refuse dumped into the river floodplain can be a significant source of invasive plant species and general habitat degradation. o Exotic Species – o The river floodplain is naturally susceptible to weedy plant invasion. The railroad rights- of-way, the utility rights-of-way and the transition zone between forested and agricultural landscapes are also areas of greatest invasive plant species concentrations.

Conservation Actions:

Overall: o Coordinate the protection of this landscape between Lancaster and York Counties. o Recognize the river floodplain as an active part of the river and establish riparian buffer protection from the upper edge of the floodplain. Protect the natural vegetation within 300 meters of the river floodplain and the integrity of the large interior forests within the adjacent uplands by avoiding additional fragmenting features such as roads, residences and utility rights-

365 Lower Susquehanna River

of-ways. A wide, naturally vegetated corridor along both sides of the river will help provide a minimal habitat and migration corridor for plants and animals in addition to help improve water quality entering the river. The protection of the wide floodplain will also help mitigate the downstream effects of flood events by providing an area where floodwaters can spread out without endangering human communities. o Encourage agricultural areas along the banks of the river and its adjacent bluffs to retreat from the river’s edge and to revert to a forested landscape. Encourage the regeneration of native trees, shrubs and herbaceous layers. The forest cover of the river slopes should be allowed to achieve and maintain old-growth characteristics. o Avoid building, replacing or expanding dams on the Susquehanna River.

Within the Core Habitat: o Preserve and improve the water quality of the Susquehanna River to help provide a continued and increased food chain. Maintain and improve water quality of the river by providing vegetated buffers along inflows to the river and along the river shoreline. o Discouraged the establishment of seasonal cottages and year-round residences along the river shoreline bluffs overlooking the river. Limit and reduce the number of seasonal cabins on the shoreline of the river. Septic systems for these structures are frequently inadequate. Disturbance on shorelines includes loss or impairment of critical habitat due to construction of cabins, access roads, boat docks, lawns and vegetation clearing. Some vegetation removal can be beneficial to the habitat, but an increase in shoreline cottages can only result in a decrease in habitat for species adapted to these specific habitat conditions. The floodplain habitat of the river would be improved by the removal of the residences within the floodplain. o Maintain and improve interior forest conditions within the uplands adjacent to the river. Avoid building roads, residences and utility rights-of-way though unfragmented patches of forest. Cluster these amenities in existing locations to avoid unnecessary habitat disturbance. o Remove invasive species of plants. The river floodplain is naturally susceptible to weedy plant invasion and will require a sustained and targeted approach to invasive management. o Target pioneer populations of invasive plants for immediate and continued removal, particularly tree-of-heaven, non-native bush honeysuckles, Japanese honeysuckle, Japanese hops, Japanese knotweed, multiflora rose, mile-a-minute and common privet. It is much easier and more effective to keep a place invasive-free than to try and repair a heavily infested habitat. o Invasive species are a significant feature of the railroad and utility rights-of-way and river shorelines. However, indiscriminate use of herbicides as rights-of-way defoliants is not acceptable. A smarter, more selective use of chemical controls is required in these areas that contain both invasive species and species of concern. o Invasive species management needs to be coordinated by individuals familiar with the rare species as well as the invasive species present. o Continual invasive species monitoring and control will be necessary.

Within the Supporting Landscape: The supporting landscape was drawn to include a 300 meter buffer to this section of the Susquehanna River and a 100-meter riparian buffer for all tributaries. Activities and land use patters in the adjacent subwatersheds can have a significant impact on the water quality of the river and the habitats of the species of concern. o Most of the conservation actions for the core habitat also apply to the supporting landscape. o Pursue conservation easements, transfer of development rights and fee simple acquisition on properties along the river shoreline, the adjacent slopes and forested plateaus to help conserve the effectiveness of the Susquehanna River natural corridor.

366 Lower Susquehanna River

o The long term goal for the area should be to restore or maintain the mature floodplain forests and the associated upland buffer forests along both shores of the river. Preserve and expand the native vegetation along the river corridor to include land within 300 meters of the river’s floodplain. Reforestation efforts should be designed to mimic the adjacent natural community type by recruiting a similar composition of native trees and shrubs of varying age classes. Reforestation is a labor intensive effort that requires long term monitoring and maintenance to avoid infestation by invasive species of plants. o Avoid additional fragmenting features such as roads, buildings, and utility rights-of-way especially along the river shoreline and any large forested blocks. Preserve and improve the integrity of the large unfragmented forest blocks on the western shore of the Susquehanna River. These large forested areas provide a significant filter for runoff entering the river from these slopes. The steep, rocky nature of the wooded slopes likely precludes most types of development activity. The flatter hilltops, however, could prove tempting building sites. Avoid activities that would fragment this habitat or create more edge areas, such as road building, which encourage the introduction of invasive plants or edge-adapted species and diminish the habitat available to interior forest dwelling species. o Avoid logging activities on slopes adjacent to the Susquehanna River to allow for the development of old growth conditions. The immediate watershed draining into the river includes some forested areas and agricultural fields. Logging of wooded areas, specifically along steep slopes and riparian borders would be detrimental to the watershed. Nutrients from agricultural fields, failures from septic systems within the watershed, lawn care fertilizers and other sources can accumulate in the river leading to algal blooms and the consequent death of aquatic organisms. The amount of impervious surfaces around the river can allow all types of chemical runoff from roads, building materials etc. to reach and contaminate the river. o Streams through forested areas should be considered high priority for conservation in the habitat. The forested riparian corridor helps to regulate the temperature of the stream and creates streamside conditions that contribute to improved water quality and aquatic habitat. Streams through non-forested areas should be restored with native trees and shrubs appropriate to the topography and hydrology. o Careful determination is needed to avoid planting trees in floodplains that contain herbaceous wetland habitats. These habitats should be maintained in their current open condition, with tree plantings to occur at the periphery of natural wetland openings. o An ideal forested stream buffer should be at least 100 meters in width from the upper edge of the 100-year floodplain. o An intermediate forested stream buffer should be at least 100 feet in width from the upper edge of the 100-year floodplain. o A minimum forested buffer should be at least 35 feet in width from the upper edge of the 100-year floodplain. o Zoning options for conservation enhancement: o Drumore and Fulton Townships have zoning ordinances restricting new construction within the 100-year floodplain of all waterways. Strict enforcement of these regulations will help prevent conversion of the floodplain to unsuitable uses and help protect most of the species of concern core habitat. o Floodplain regulations should be updated to prohibit agricultural activities within the 100-year floodplain as well. Chemical, nutrient and sediment runoff into waterways from agricultural sources can be significantly reduced by returning seasonally flooded areas to natural habitats. o Strict enforcement of regulations restricting building activity on slopes greater than 25% would help prevent the forested slopes from being converted to other uses. o Zoning regulations should discourage further fragmentation of contiguous or interior forest blocks. Parcels currently forested should be zoned to conserve this attribute.

367 Lower Susquehanna River o Parcels currently in agriculture that are of high quality agricultural soils should be zoned agricultural and considered fully built-out. Poorer quality agricultural soils and those within the 100-year floodplain should be encouraged to regenerate into forest cover. o Growth within the Township should be discouraged to occur within 300 meters of the 100-year floodplain of the Susquehanna River, or within 100 meters of the floodplain of its tributaries. o Growth should be encouraged to occur clustered in close proximity to existing infrastructure to avoid unnecessary habitat destruction, particularly along the shoreline of the Susquehanna River.

368 Lower Susquehanna River

369