Oxbow Lake/Pond
Air photo of oxbow lake along Genesee River near Geneseo, NY
System
Lacustrine
Subsystem
Natural Lakes And Ponds
Did you know?
Geographically distinct variants of oxbow lake
occur in New York and differ in dominant and
characteristic vascular plants, fishes, mollusks, and
insects. In addition, three morphological variants
are also known in New York: 1) classical oxbow
lakes formed from old river channels, 2) small
levee lakes formed as pools from levee overwash,
and 3) floodplain lakes formed and replenished
during high annual water of the associated river.
Photo credits: NYS Digital Orthoimagery Program
Summary
Protection Not listed in New York State, not listed federally.
Rarity G4, S3
A global rarity rank of G4 means: Apparently secure globally, though it may be quite rare in
parts of its range, especially at the periphery.
A state rarity rank of S3 means: Typically 21 to 100 occurrences, limited acreage, or miles
of stream in New York State.
Conservation Status in New York
There are probably several hundred occurrences statewide, although most are likely small
and degraded. Very few documented occurrences have good viability and few are
protected on public land or private conservation land. This community is somewhat limited
to the floodplains of large streams and rivers across the state, and includes very few large,
high quality examples. The current trend of this community is probably stable for
occurrences on public land and private conservation land, or declining slightly elsewhere
due to moderate threats related to development pressure. This community has declined
substantially from historical numbers likely correlated with past hyrdorlogical alterations,
conversion to agriculture, and other development.
Short-term Trends
The number and acreage of oxbow lakes on the floodplains of unconfined rivers in New
York have probably remained stable in recent decades as a result of water quality
regulations.
NYNHP Conservation Guide - Oxbow Lake/Pond
Long-term Trends
The number and acreage of oxbow lakes on the floodplains of unconfined rivers in New
York are probably comparable to historical numbers.
Larger occurrences of this natural community (>12.5 acres) are protected under NY State
wetland laws.
Conservation and Management
Threats
Oxbow lakes are threatened by development (e.g., residential, agricultural) in the
surrounding landscape. Other threats include habitat alteration (e.g., road crossings,
excessive logging in adjacent floodplain), and relatively minor recreational overuse (e.g.,
ATVs, trampling by visitors). Threats to adjacent rivers may apply to oxbow lakes (e.g.,
channelization, pollution, nutrient loading, sedimentation, impoundments/flooding).
Conservation Strategies and Management Practices
Where practical, establish and maintain a riparian buffer to reduce storm-water, pollution,
and nutrient run-off, while simultaneously capturing sediments before they reach the oxbow
lake. Buffer width should take into account the erodibility of the surrounding soils, slope
steepness, and current land use. If possible, minimize the number and size of impervious
surfaces in the surrounding landscape. Avoid habitat alteration within the river and
surrounding landscape. For example, roads should not be routed through the riparian
buffer area. If the oxbow lake must be crossed, then bridges and boardwalks are preferred
over filling and culverts. Restore past impacts, such as removing obsolete impoundments
and ditches in order to restore the natural hydrology. Prevent the spread of invasive exotic
species into the oxbow lake through appropriate direct management, and by minimizing
potential dispersal corridors.
Development and Mitigation Considerations
When considering road construction and other development activities, minimize actions
that will change what water carries and how water travels to this community, both on the
surface and underground. Water traveling over-the-ground as runoff usually carries an
abundance of silt, clay, and other particulates during (and often after) a construction
project. While still suspended in the water, these particulates make it difficult for aquatic
animals to find food; after settling to the bottom of the system, they bury small plants and
animals and alter the natural functions of the community in many other ways. Thus, road
construction and development activities near this community type should strive to minimize
particulate-laden run-off into this community. Water traveling on the ground or seeping
through the ground also carries dissolved minerals and chemicals. Road salt, for example,
is becoming an increasing problem both to natural communities and as a contaminant in
household wells. Fertilizers, detergents, and other chemicals that increase the nutrient
levels in wetlands cause algal blooms and eventually an oxygen-depleted environment in
which few animals can live. Herbicides and pesticides often travel far from where they are
applied and have lasting effects on the quality of the natural community. So, road
construction and other development activities should strive to consider: 1. how water
moves through the ground, 2. the types of dissolved substances these development
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activities may release, and 3. how to minimize the potential for these dissolved substances
to reach this natural community.
Inventory Needs
Survey for occurrences statewide to advance documentation and classification of oxbow
lakes (e.g., Genesee River). A statewide review of oxbow lakes is desirable. Continue
searching for large oxbow lakes in good condition (A- to AB-ranked) preferably comprised
of multiple waterbodies of varriable size and depth.
Research Needs
Research is needed to fill information gaps about oxbow lakes, especially to advance our
understanding of their classification, hydrology, floristic variation, and characteristic fauna.
In addition, there is a need to collect sufficient quantitative data to support the recognition
of a smaller variant tentatively called "oxbow pond" or change the current name to "oxbow
lake/pond" and broadened the concept.
Rare Species
Mountain Watercress (Cardamine rotundifolia)
Identification Comments
An oxbow lake is a small, shallow, usually stagnant lake or pond of fluvial origin that occurs
in an old river meander or oxbow that has been cut off from an unconfined river or marsh
headwater stream by deposition of a levee on both upstream and downstream ends.
Typically, the associated river periodically overflows this levee, restoring river water and
biota to the lake. Many examples of this lake type may be relatively short-lived in dynamic
river complexes, transforming either into backwater sloughs through permanent breaching
of the downstream levee, or into riverine communities through permanent breaching of the
upstream levee. Oxbow lakes are usually eutrophic.
The Best Time to See
The flora of oxbow lakes is at its peak in mid to late summer. Aquatic plant species such as
water lobelia and bladderwort can be observed in bloom at this time.
Characteristics Most Useful for Identification
Oxbow lakes are completely separated from their associated riverine community most of
the year during an average year. The river should generally overflow the dividing levee
once or more every five years, otherwise the occurrence may grade into a eutrophic pond.
Characteristic biota are typically riverine species assemblages. Aquatic macrophytes may
include species typical of eutrophic ponds such as pondweeds (Potamogeton spp.), white
water-lily (Nymphaea odorata), and water-shield (Brasenia schreberi). Associated shrub
and herbaceous vegetation can vary widely by ecoregion and by the surrounding floodplain
vegetation. Characteristic fauna may include odonates (Odonata).
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Elevation Range
Known examples of this community have been found at elevations between 1550 feet and
1575 feet.
Similar Ecological Communities
Backwater slough: Backwater sloughs are onlyseparated from an associated riverine by a
levee at their upstream end. Oxbow lakes are cut off completely.
Eutrophic pond: Eutrophic ponds do not receive overflow from an associated riverine
community. Oxbow lakes are flooded by an associated river once or more every five years.
Characteristic Species
Shrubs < 2m
Red Maple (Acer rubrum)
Speckled Alder (Alnus incana)
Leatherleaf (Chamaedaphne calyculata)
Tamarack (Larix laricina)
Sweet Bayberry (Myrica gale)
Hardhack Spiraea (Spiraea tomentosa)
Northern White Cedar (Thuja occidentalis)
Herbs
Porcupine Sedge (Carex hystericina)
American Woollyfruit Sedge (Carex lasiocarpa)
Beaked Sedge (Carex utriculata)
Tawny Cotton-grass (Eriophorum virginicum)
Flat-top Fragrant Goldenrod (Euthamia graminifolia)
Canada Manna-grass (Glyceria canadensis)
Marsh St. John's Wort (Triadenum virginicum)
Submerged aquatics
Potamogeton spp.
Shrubs < 2m
Herbs
Submerged aquatics
0
20
40
60
80
100
This figure helps visualize the structure and "look" or "feel" of a typical oxbow lake/pond. Each bar represents the amount
of "coverage" for all the species growing at that height. Because layers overlap (shrubs may grow under trees, for
example), the shaded regions can add up to more than 100%.
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Additional Resources
Links
Oxbow on the Raquette River
https://www.youtube.com/watch?v=EOvkzL8lZOE
References
Edinger, G. J., D. J. Evans, S. Gebauer, T. G. Howard, D. M. Hunt, and A. M. Olivero (editors).
2014. Ecological Communities of New York State. Second Edition. A revised and expanded
edition of Carol Reschke’s Ecological Communities of New York State. New York Natural
Heritage Program, New York State Department of Environmental Conservation, Albany,
NY. http://www.dec.ny.gov/docs/wildlife_pdf/ecocomm2014.pdf
Edinger, Gregory J., D.J. Evans, Shane Gebauer, Timothy G. Howard, David M. Hunt, and Adele M.
Olivero (editors). 2002. Ecological Communities of New York State. Second Edition. A revised
and expanded edition of Carol Reschke's Ecological Communities of New York State. (Draft for
review). New York Natural Heritage Program, New York State Department of Environmental
Conservation. Albany, NY. 136 pp.
Keys, Jr.,J.; Carpenter, C.; Hooks, S.; Koenig, F.; McNab, W.H.; Russell, W.;Smith, M.L. 1995.
Ecological units of the eastern United States - first approximation (cd-rom), Atlanta, GA: U.S.
Department of Agriculture, Forest Service. GIS coverage in ARCINFO format, selected imagery,
and map unit tables.
NatureServe. 2005. NatureServe Central Databases. Arlington, Virginia. USA
New York Natural Heritage Program. No date. Field forms database: Electronic field data storage
and access for New York Heritage ecology, botany, and zoology. New York Natural Heritage
Program, New York State Department of Environmental Conservation. Albany, NY.
Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage
Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus
xi.
Smith, C.L. 1985. The Inland Fishes of New York State. New York State Department of
Environmental Conservation. Albany, NY. 522pp.
New York Natural Heritage Program
This project is made possible with funding from:
625 Broadway, 5th Floor,
- New York State Department of Environmental Conservation Hudson River
Albany, NY 12233-4757
Estuary Program
Phone: (518) 402-8935
- Division of Lands & Forests, Department of Environmental Conservation
[email protected]
- New York State Office of Parks, Recreation and Historic Preservation
Information for this guide was last updated on Apr 05, 2017
This guide was authored by Gregory J. Edinger
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