2016 Annual Report

Falconbridge Pond Advisory Committee

Creating a Common Vision for the Future of Falconbridge Pond

The Falconbridge Pond Advisory Committee was created in late spring 2016 by Falconbridge Homeowners Association President Ron Johnston following a disastrous cyanobacteria (blue-green algae) bloom that virtually eliminated the fish population.

The committee consists of a chair and five voting members. Under the terms of organization, the chair and three of the voting members are members of FHA, the organization of 163 townhome owners, and two are members of Falconbridge Community Association, the voluntary HOA of single-family homeowners. Regardless of affiliation, however, all members of the advisory committee are challenged by the need tobalance our idealized vision of the pond with realistic and reasonable expectations of what the two organizations together can achieve.

Our five-acre pond (its size is an updated figure calculated in 2016 by the City of Durham’s Geographical Information Services staff) was built in the 1930s as a farm pond.Because no natural springs or seeps feed into it, all of the pond’s water comes from surface runoff – essentially stormwater, which flows in from 38 surrounding acres via street drains, downspouts and natural swales. (See appendix, Falconbridge Pond)

This drainage area (the watershed, as delineated on the accompanying map) includes 56 townhomes and 38 single family homes, plus the clubhouse and pool, tennis courts,and a small portion of the Falconbridge commercial center. More than 30 percent of the watershed consists of rooftops and paved surfaces such as streets, driveways and parking areas.

None of the precipitation falling on these areas has a chance to soak into the ground before flowing into the pond. Consequently, the pond receives motor oil and other petroleum products, heavy metals, and other contaminants such as phosphorous and nitrogen common in fertilizer runoff from urban/suburban neighborhoods.

Unfortunately, the goal of natural or pristine water quality is unrealistic under such circumstances. Thus the committee’s best assessment of the pond’s current state as 2017 begins is “fair,” a rating based on a scale from poor to excellent.

So, what might we reasonably expect the from our pond and, just as important, what can we do to assure its long-term health? Below is a list of amenities that we believe will benefit and help sustain our pond – the possessive emphasis extends to the entire Falconbridge community – as a signature amenity of an environmentally aware neighborhood. In fact, a pond of this size is such a rarity among Research Triangle neighborhoods that it not only deserves careful maintenance but also full community use.

The remainder of our report discusses the ways we might achieve these amenities.

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What we should expect from our pond

Water Quality – The water should generally appear clean, rather than green and mucky, but we should not expect it to have the “sky blue” transparency of natural ponds or lakes in the northern United States.

Water Depth – Except for the immediate shoreline, all areas of the pond should be at least three feet deep when the pond is full. This is the depth necessary for natural control of invasive woody vegetation such as black willow.

Access – All townhome and single-family residents should be able to enjoy the pond for walking, picnicking, shoreline fish-and-release or simply resting on a tree-shaded bench. To that end, the committee recommends topping the trail atop the dam with Chapel Hill gravel, an inexpensive, all-weather material that will keep pedestrians out of the mud.

Fish Population – Although desirable, it is probably unrealistic to expect the pond to support large numbers of an apex fish species such as largemouth bass, although the committee likely will release a small number of bass into the pond in fall 2017 on an experimental basis. It is reasonable, however, to expect the pond to support a healthy population of pan fish such as bluegill and catfish. Bluegill in particular are prolific breeders.

At least 15 sterile carp, which feed exclusively on aquatic weeds, should be maintained in the pond at all times. That is the number introduced in fall 2016 following losses in the fish kill . In addition to the carp, the pond committee bought three pounds of fathead minnows, 20 channel catfish (bottom feeders) and 300 bluegill in 2016. These fish were purchased with $454.80 donated by members of the pond advisory committee.

These numbers are very low for a five-acre pond. However, the pond committee, concerned about water quality and the possibility of another cyanobacteria bloom this spring, is comfortably cautious with the low quantity. Fortunately, bluegill and minnows are prolific breeders and, given proper conditions and enough time, will produce pan-sizedescendants well beyond their initial stocking.

Wildlife and Vegetation – We should strive to manage the pond and its environs in ways that support a wide variety of birds, mammals, reptiles, crustaceans and freshwater shellfish as well as desirable trees, shrubs and grasses. Extension of the riparian buffer, 36 inches wide and no more than 24 inches high, along the entire perimeter of the pond, which FHA controls, would do its part to help support our wildlife population.

What we should do to ensure the future of the pond

Community Awareness – Nothing is more vital to the future of Falconbridge Pond that a strong, shared sense of its value to our community, both townhome and single-family. Efforts to raise community awareness and access to the pond should be made via newsletter articles, wildlife and vegetation pamphlets, nature walks and other activities discussed below.

Watershed Stewardship — The 2016 fish kill was almost certainly the result of a perfect storm of temperature, heavy rainfall and excessive nutrients such as nitrogen andphosphorus that triggered exponential growth of cyanobacteria, which in turn led to

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rapid depletion of life-sustaining oxygen in the water. Such events will likely recur because of the pond's urban/suburban nature.

We must manage the pond using best practices that keep cyanobacteria, which is found in all ponds and lakes, in check. To that end, the pond committee recommends that all townhome and single-family homes within the pond watershed be given an 11- by 14-inchcopy of the GIS watershed map. The map should be accompanied by a letter from the appropriate HOA advising homeowners to use low-nutrient, slow-release fertilizer, or if possible no fertilizer, during the spring growing season. The map and letter should be delivered to each townhome and single-family home within the pond watershed by mid-February.

The great dying of May 2016 was almost certainly due due to a “perfect storm” of temperature, rainfall and nutrients such as nitrogen and phosphorus that triggered a massive cyanobacteria (blue-green algae) bloom and subsequent depletion of life-sustaining oxygen. Such events will likely recur because of the pond’s urban/suburban nature. We must manage the pond in ways that minimize the future probability of such costly events.

Pond Desilting — The northeast and southeast lobes of the pond have accumulated large amounts of sediment over the last 80 years, severely limiting water depth. Removal of this sediment will be a costly project, one requiring a major commitment from the entire Falconbridge community. The pond committee is seeking reliable estimates of the cost and neighborhood impact of achieving the desired three-foot minimum depth mentioned above.

Dam Maintenance and Safety— In cooperation with the FHA Landscape Committee, the pond committee has assumed weed and woody vegetation management on the wet and dry fronts of the dam. This work is voluntary. However, certain aspects of dam maintenance must remain with FHA, which owns the the dam, the lake and the shoreline,varying from 15 to 100 feet inland. For instance, overflow during the spring 2016 rains carved a runoff channel on the dry face of the dam, a worrisome development that needs to be corrected.

This channel, about a foot wide and several inches deep, presents a long-term threat to the integrity of the structure. It probably can be be eliminated with grassy sod, the same remedy that stopped similar erosion almost 20 years years ago along the overflow channel at the northern end of the dam. In addition, although our dam complies with all North Carolina safety requirements, state inspector John Holley noted in 2016 that a plan for emergency notification and evacuation of downstream residents ought to be in place should the need ever arise.

In the meantime, the committee recommends that FHA consider placement of sandbags in a semi-circle around the outflow regulator valve to reduce runoff across the dam and down the erosion channel.

Pond wildlife and vegetation pamphlet — With modest funding, the pond committee can produce a walk-about pamphlet suitable for both adults and children describing the varied wildlife and vegetation associated with the pond. The committee plans to have the pamphlet ready by the opening of pool season 2017.

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Pond nature walks — As a corollary, the pond committee plans to develop seasonal narrated nature walks around the pond for adults and, especially, the children of Falconbridge. Many people in Falconbridge know of the pond, but comparatively few know much about the pond. Trees, shrubs and plant s will be identified with all-weather markers for these nature walks designed to introduce all ages to the crown jewel of our neighborhood.

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In closing, the Falconbridge Pond Advisory Committee wishes to express its appreciation for support during its inaugural year from Falconbridge Homeowners Association and Falconbridge Alliance. We look forward to working with you in 2017.

Respectfully submitted by the Falconbridge Pond Advisory Committee, Bob Wilson, chairman, and committee members Mike Mayo (FHA), Kathy King (FHA), Amelia Matthews (FHA), Ed Holland (FCA) and Van Noah (FCA). A special note of gratitude to Ed Holland, who contributed to production of the GIS watershed map.

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Drainage to Falconbridge Pond

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Falconbridge Drainage Features

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0 400 800200 Feet

Map prepared by Durham GIS on 5/26/2016

Information depicted hereon is for reference purposesonly and is compiled from the best available sources.

The City of Durham/Durham County assumes no responsi-bility for errors arising from use or misuse of this map.

Basemap provided by ESRI via ArcGIS Online.

● Pond Surface Area = 4.9 acres

● Watershed Area (Drainage to Pond) = 38.1 acres.

Bw/Wb/Df A Bb B Total

Number of Homes in Watershed 42 14 56 38 0 94

Number of Homes Adjacent to Pond 21 0 21 11 0 32

Impervious (Acres) D 2.8 1.0 3.8 5.3 3.0 12.1

Impervious (% of Watershed) D 7.3% 2.6% 10.0% 13.9% 7.9% 31.8%

A Bayswater, Weybridge, Dartford AreaB Bloomsbury AreaC Clubhouse Area + Portion of Falconbridge Commercial CenterD Rooftops and Paved surfaces: Walkways, Roadways, Driveways & Parking Areas

Other Factoids

● 1 "acre-foot" = 1 acre of water 1 foot deep = 326,000 gallons. So, if the pond is an

average of, say, 3 to 4 feet deep, it would contain 3 to 4 ft x 4.9 acres = 14.7 to 19.6 acre-feet,

or 4.8 to 6.4 million gallons of water -- which is 50 to 70 times more than the Falconbridge swimming pool.

● One inch of rain falling on the 38.1 acres of homes, yards, and pavement draining to the pond

represents about 1 million gallons of water. Much of this falls on impervious surfaces

(roofs, roads, driveways, and parking areas) and flows almost directly into the pond - along

with acculmulated contaminants from those surfaces.

Townhomes Single

Family

Commercial &

Other CWatershed

Total

Falconbridge Pond -- Watershed Factoids