|* Flat Creek Restoration|
Preservation and Restoration of NJDEP Ambient Biological Monitoring Station AN0459 – Flat Creek at
Bayshore Regional Watershed Council
T & M Associates, Inc.
Phone : (732) 671-6400
Fax: (732) 671-7365
Eric E. Nathanson
Senior Environmental Scientist
HOLM-05650 October 2006
The following report has been prepared on behalf of the Bayshore Regional Subwatershed Council (BRSC). The BRSC, through the
The monitoring station is located on Flat Creek at
As per the New Jersey Department of Environmental Protection (NJDEP) –Division of Watershed Management, the Flat Creek Subwatershed is located within Watershed Management Area 12 – Atlantic Region. Flat Creek is approximately five (5) miles in overall length. Its course runs in a northerly direction from
The following findings report was developed by qualitatively analyzing the overall drainage area and prevailing land uses in the Flat Creek Subwatershed. Specific attention was paid to identifying known and suspected sources of watershed pollution. In addition, existing information collected by the BRSC and its partners was also reviewed and incorporated where applicable. This information includes available mapping, water quality sampling data, results of past stream corridor surveys, and color photographs. Lastly, the latest round of NJDEP benthic macroinvertebrate sampling data was reviewed in order to establish a benchmark for this ongoing study. The data were collected at the AMNET Monitoring Station in 1999.
1.0 Ambient Biomonitoring Network
Station AN0459 is part of the NJDEP Ambient Biomonitoring Network for Watershed Management Areas 12-16 in the Atlantic Region. The current network, established in 1992 by the NJDEP, has been developed from State research efforts dating from the 1970’s. The research efforts continue to utilize benthic macroinvertebrate data collected from both long-term ambient monitoring and short-term intensive surveys. It has long been established that benthic macroinvertebrates of various trophic levels are effective indicators of water pollution. As such, the data is used as an important tool in implementing water quality management and land use planning policies throughout the State’s watersheds.
The NJDEP’s Bureau of Freshwater and Biological Monitoring (BFBM) currently oversees the sampling and analysis of data collected from over 800 stations within the Ambient Biomonitoring Network. As per current BFBM protocol, sampling is conducted every five (5) years. In addition to developing water quality management and land use planning policies, the data are used to comply with federal regulations. Specifically, the regulations, as mandated by the US Environmental Protection Agency, require all States to generate a biennial Water Quality Inventory Report (305b Report) and maintain a list of impaired streams (303d List). The data used to develop this findings report were taken from the second round of AMNET sampling for Watershed Management Area 12. The first data set was developed in 1994.
2.0 Biological Monitoring and Use of Benthic Macroinvertebrate Data
For the purposes of this report, biological monitoring pertains to the collection and subsequent analysis of individual organisms that comprise the macroinvertebrate community found at Station AN0459 on Flat Creek. In general, benthic macroinvertebrates are easily collected from stream beds and can be readily seen with the naked eye. Individual macroinvertebrates are collected using dip nets, kick nets, and similar devices. Captured specimens are preserved in the field prior to lab analyses. A typical community contains insects (primarily immature forms), worms, mollusks, and crustaceans. Presence and relative abundance of the individual species in any given community is largely a function of water quality. Benthic macroinvertebrates of various trophic levels are generally stationary organisms that live in the substrates of streams and estuaries. Since the benthic macroinvertebrate community is less motile than other types of aquatic wildlife, they integrate the effects of prevailing environmental conditions and habitat changes. As such, scientists rely upon the benthic macroinvertebrate community to assist them in characterizing the water quality of a stream or estuary. Specifically, a rich and diverse macroinvertebrate community is indicative of a stream bed with good water quality. Similarly, a community that is dominated by pollutant tolerant species is indicative of an impaired stream bed with poor water quality. It is important to note, however, that scientists do not solely rely upon the composition of a benthic macroinvertebrate community in order to ascertain water quality. Various chemical and toxicity tests are equally important in characterizing the water quality of a stream or estuary.
In general, stream beds with a rich and diverse benthic macroinvertebrate community characteristically contain stable banks with a dense canopy of vegetation along each side, highly oxygenated lotic (i.e., running) surface flow with riffle and run areas, and a substrate comprised of stone and gravel of various sizes. Stream beds exhibiting these types of habitat characteristics will also contain pollution-sensitive taxa such as the EPT group. The EPT group refers to the taxonomic Orders of Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies). Such “high gradient” streams are often located in the more remote northern portions of the State. They can be found in the
Biologically impaired streams are slow moving, lack undisturbed bank vegetation, and contain substrates made of fine particulate matter. In addition, these types of streams are turbid, lack dissolved oxygen, and typically receive drainage carrying pollutants from various sources. These degraded streams are often found in urbanized areas subject to extensive development and various forms of land disturbance. The many forms of land disturbance (e.g., industrialization, agriculture, residential construction, etc.) often result in the discharge of sediment laden run-off that contributes to the ongoing degradation of impaired streams.
3.0 NJDEP Ambient Biological Monitoring Station AN0459
Monitoring Station AN0459 is one of 213 sampling sites located within Watershed Management Areas 12 through 16 – Atlantic Region. This includes those basins that drain to the Atlantic Ocean, Raritan and
Biological monitoring of the benthic macroinvertebrate community at Station AN0459 was conducted by the BFBM in 1994 and 1999. The results of the 1999 sampling indicate that the macroinvertebrate community and Flat Creek Subwatershed are both severely impaired. As such, Flat Creek has been placed on Sub-list IIA of the 1998 List of Water Quality Limited Waters (303d List). Flat Creek has also been added to Sub-list 5 of the 2002 and 2004 New Jersey Integrated List of Waterbodies.
Biological monitoring results generated at Station AN0459 are largely a function of the prevailing land use in the subwatershed. The Flat Creek Subwatershed primarily receives drainage from a densely urbanized portion of
It is important to note, however, that since these data were generated, agricultural land cover throughout the watershed has been reduced due to recent development.
4.0 Habitat Assessment at Monitoring Station AN0459
The stream bank habitat immediately adjacent to Monitoring Station AN0459 is degraded. The banks of Flat Creek at the monitoring station are severely eroded and lack dense vegetation. Specifically, less than fifty percent of the stream bank surfaces are covered by vegetation. This is the result of disturbances associated with adjacent development and impacts from human intrusion. Since the stream bank vegetation is thin and disturbed, Flat Creek has become subject to persistent sedimentation. A dense vegetated cover along the banks would provide some primary water quality treatment (i.e., filtration) before stormwater enters Flat Creek. However, untreated surface water runoff entering Flat Creek at the monitoring station carries an elevated load of suspended solids that are generated from nearby impervious surfaces. Flows during storm events also contribute to the ongoing sedimentation and erosion problem because the area lacks dense vegetation that would otherwise slow stormwater entering Flat Creek. As a result, the structural integrity of the banks has become compromised.
Since the area lacks features that would provide primary water quality treatment, Flat Creek is subject to excessive sedimentation. This has a direct result on the substrate composition near the monitoring station. Instead of a mix of snags, submerged logs, cobble of various sizes, or similar stable habitats, the substrate near the monitoring station consists of an accumulation of fine sediments, obvious depositional areas, exposed hard pan clay and bedrock due to scour, and a flat stream bed that cannot support a colonization of benthic macroinvertebrates. The area also lacks pool variability and riffle-run areas that would normally support submerged aquatic vegetation and a diverse community of benthic macroinvertebrates. Lastly, snags upstream of the monitoring station slow the stream flow and reduce the overall riparian width of the stream. The reduced flow rate and riparian width impacts ambient levels of dissolved oxygen.
It should be noted that discharge points located throughout the Flat Creek watershed far upstream of the monitoring station are also contributing to its degradation. The BRSC collected data (e.g., photos, locations, etc.) relative to these discharge points during a stream walk that was conducted in July 2005. The discharge points include drain pipes associated with private residential sites and municipal stormwater management infrastructure. The water discharged from these sources contributes to poor water quality and sedimentation. In many cases, soil surrounding municipal infrastructure has eroded which has caused the headwalls to fall into the stream bed. Overall improvement of the Flat Creek watershed is partially contingent upon eliminating unnecessary discharge points and replacing defunct infrastructure.
5.0 Biological Monitoring Results at Station AN0459
The degraded conditions of the Flat Creek Subwatershed have adversely impacted the benthic macroinvertebrate community at Station AN0459. The following table presents the 1999 biological monitoring results collected by the BFBM.
The results presented in the table above are indicative of a community suffering from biological impairment. The community is dominated by pollution-tolerant families represented by Sphaeriidae (fingernail clams), Chironomidae (midges), Asellidae (isopods), and Tubificidae (oligochaetes). Specifically, the dominant families have high pollution tolerance levels (FTV) and are able to withstand organic enrichment (i.e., eutrophication), habitat degradation, and toxicological effects. It is important to note that the FTV is inversely proportional to water quality indices.
The results also indicate that the community is suffering from an overall lack of diversity. Of the ten families represented, four comprise 92% of the sub-sample collected during the 1999 biological monitoring event. Although the overall New Jersey Impairment Score (NJIS) Rating for Watershed Management Area 12 has slightly improved since the 1994 sampling efforts, poor water quality continues to impact the benthic macroinvertebrate community. Unless the existing habitat conditions and water quality is improved, the current community trend will persist and possibly worsen. As such, the absence of pollution-intolerant taxa represented by the EPT group will continue. More importantly, raising the NJIS for Flat Creek will not be possible. In order to improve water quality at the monitoring station, efforts need to be concentrated in the headwaters of Flat Creek upstream of
The BFBM’s 2004 sampling data were not available at the time this report was finalized. As such, comparison of the 2004 and 1999 data was not conducted. It is important to note, however, that the Rutger’s Cooperative Extension performed water quality and benthic macroinvertebrate sampling at the monitoring station on
6.0 Role of the Bayshore Regional Watershed Council
The Bayshore Regional Subwatershed Council (BRSC) has partnered with the Townships of Holmdel and Hazlet, the Freehold Soil Conservation District, the Monmouth County Planning Board, the Monmouth County Mosquito Extermination Commission, and the Monmouth County Watersheds Partnership in order to obtain a better understanding of the relationship between the benthic macroinvertebrate community at Station AN0459 and the water quality of the Flat Creek Watershed. This partnership has brought together regional experts and concerned citizens to preserve and ultimately improve the water quality of Flat Creek. Improving the water quality will, overtime, have a significant impact on the benthic macroinvertebrate community at the monitoring station.
To date, the BRSC partership has conducted a number of site investigations at various locations throughout the Flat Creek Subwatershed. The goals of these site investigations are numerous. The primary goal, however, is to identify the main sources of pollution that is degrading the subwatershed. Although the BRSC partnership recognizes that the shift in land use from agriculture and undisturbed open space to urban development is a primary contributing factor to the subwatershed’s current condition, additional secondary factors (i.e., non-point sources) must be identified. As such, the only way to truly gain perspective on non-point sources of pollution is to actually walk the length of the subwatershed.
The BRSC conducted stream walks during the summer and fall months of 2005. A photographic record of the stream walks was generated in order to maintain an inventory of those areas in the subwatershed that require corrective action. The photographic record documents the location of municipal and residential discharge points, dumping areas, areas of accumulated organic matter, and locations where retaining walls and other structures have altered the flow of water through Flat Creek. Representative photographs are presented in Attachment A. Special attention was also focused on snagged areas within the stream that are creating obstructions to flow. Areas associated with snagged portions of Flat Creek are subject to flooding and often display obvious differences in mean water elevation.
As a result of these efforts, the BRSC has gained a comprehensive understanding of the physical conditions of the entire subwatershed and have identified those areas that are currently contributing to the ongoing sedimentation and erosion of Flat Creek. Such areas include unstable stream banks, areas of undefined stream banks, and ponded/dammed areas. This understanding bolsters the widely recognized fact that Flat Creek exhibits a poor ability to handle a high volume of storm water which results in flooding, loss of private property, and stormwater infrastructure failure. These problem areas must be corrected in order to improve the water quality and benthic macroinvertebrate community ratings of Flat Creek.
Complementing the physical investigation of the stream corridor itself, the BRSC partnership has collected a significant amount of information pertaining to storm drain and sewer outfall locations that discharge to Flat Creek. This is an important step in assisting regional municipalities identify potential problems with the existing storm water and sewer infrastructure. In addition, locating storm and sewer drains that discharge directly to Flat Creek has created an opportunity for community involvement. Specifically, this effort builds upon a public outreach program that was originally sponsored by the New York/New Jersey Estuary Program to educate residents on watershed protection. Through this effort, residents of Hazlet, Holmdel, and
Most recently, the BRSC partnership has concentrated its efforts in collecting information pertaining to water quality indices. Specific parameters include temperature, conductivity, dissolved oxygen, pH, nitrate levels, turbidity, and chlorophyll. Although this latest effort has not yet resulted in an accumulation of a large data set, the effort is ongoing and will ultimately be used to develop baseline information to which subsequent water quality sampling data can be compared. As such, the BSRC partnership can gauge its success after corrective actions have been implemented. Water quality sampling data collected in January, March, and April 2006 is presented in Attachment B.
7.0 Flat Creek Subwatershed Improvement Recommendations
Although efforts continue to be focused on obtaining baseline information pertaining to the physical and chemical parameters of the Flat Creek Subwatershed, additional steps towards improving its impairment must be taken. This crucial part of the project’s planning phase will assist the BSRC partnership in identifying the most environmentally and cost effective measures to achieve its goal in raising the NJIS at Station AN0459. However, before these measures can be implemented, additional research is recommended. The following steps should be taken prior to identifying what corrective measures will be most effective.
1. GPS Survey – The partnership should conduct a comprehensive survey of the entire Flat Creek Subwatershed to pinpoint the exact location of all discharge points that may be contributing to the current degradation of the stream corridor. Such discharge points include outfall structures, drainage pipes, and systems that drain from residential properties. This can be accomplished by contracting a qualified firm to locate discharge points with Global Positioning System technology. A subsequent map can be developed from the GPS data to assist the partnership in strengthening its public outreach program and selecting the most appropriate corrective action. The results of the GPS Survey should also be made available to Code Enforcement Personnel in the local municipalities for possible corrective/enforcement action.
Based on conversations with members from the BRSC who have walked the entire stream corridor, it is anticipated that field work associated with completing such a survey would take approximately 60 man hours. This translates to -hour days for a two man crew. After the field work is completed, the GPS data can be post-processed and used to create the map referenced above. A qualified GIS technician should be able to develop the map in approximately ten hours. Based on current consulting rates at T&M Associates, the total estimated cost for conducting the survey and creating the map is $7000.00. It is important to note that this cost is limited to the survey and map preparation and does not include costs for direct expenses, duplication services, or other unidentified services. Completion of the survey is not considered a regulated activity and will not require State or Federal authorization.
2. Water Quality Monitoring – The BRSC partnership and its volunteers must continue to conduct water quality monitoring at established locations throughout the watershed. It is imperative, however, that sampling be regularly conducted at the monitoring station. The baseline data that are generated can be compared to subsequent data that are collected after corrective measures are taken. Comparisons of water quality data made after corrective measures are taken should be used as a tool to determine the effectiveness of any and all corrective steps. Water quality monitoring does nor require State or Federal authorization.
3. Sediment Sampling – Representative stream bed locations in close proximity to current or former agricultural facilities should be sampled for historic pesticides. Sediment sampling is an effective tool in identifying non-point sources of runoff containing pollutants that contribute to the eutrophication of the watershed.
After the above preliminary steps are taken, the following recommendations should be implemented in the order they appear:
Bio-eroison logs are readily available from a variety of suppliers. The logs generally come in ten-foot lengths and range in diameter from 10 to 20 inches. Average prices for bio-erosion logs range between $80 and $180. Bio-erosion logs provide protection from high water velocity and an area for the regrowth of native riparian vegetation. Once staked into the banks of appropriate sections along the stream corridor, the bio-erosion logs can be planted with native herbaceous plants. A seed mix containing fox sedge, wild rye, soft rush, wool grass, vervain, blue flag, ironweed, and goldenrod would provide long-term soil stability and improved stream corridor habitat. The recommended seeding rate is approximately 15 pounds per acre. The average price for the seed mix is approximately $50 per pound. The seeding effort can be highlighted as part of the community outreach program. The BRSC can contact local organizations to assist in completing the seeding effort on a volunteer basis.
Although habitat improvement is strongly encouraged by State and Federal regulatory agencies, various land use permits must be obtained prior to undertaking any activities. In particular, the NJDEP’s Land Use Regulation Program must authorize one or more land use permits prior to conducting habitat improvement activities.
3. Funding – The BRSC must continue to spend time seeking additional sources of funds for watershed improvement projects. Once funding sources are identified, a grant writer or similar individual associated with the BRSC should be charged with the task of securing additional money in order to plan future improvement projects.
After these initial steps are taken, the BSRC partnership can begin its research into future site-specific corrective measures. The following corrective measures can be collectively referred to as Best Management Practices (BMPs). These BMPs can include, but are not limited to, the following: