Research

One function of the DCSWCD is to focus or coordinate technical and educational resources to benefit local land users. Although DCSWCD is not a research organization, from time to time opportunities arise to develop and assemble local information that is not available elsewhere. Such efforts are designed to support the objectives of Delaware County’s Action Plan for watershed management (DCAP).

Published studies:

Compost Encapsulation for Treatment of Soil Infested by Polygonum cuspidatum (Japanese Knotweed). L. Day and S. McIntyre. 2016. Ecological Restoration Vol. 34, Nunber 3, Pages 184-187.

Summary: Most of us are familiar with the broad-leaved invasive plant Japanese Knotweed (Polygonum cuspidatum, among other Latin names), locally known as “bamboo.” And most of us know that applications of compost tend to help plants grow better. So who would expect that compost could be used to kill Japanese Knotweed roots in soil? In an 2016 edition of the journal Ecological Restoration, Larry Day (DC SWCD) and Susan McIntyre (DC DPW) explain how they found an unconventional method of using compost to treat soil infested with knotweed. Efforts to control the spread of this plant are important because of its tendency to dominate stream bank vegetation while increasing stream corridor instability.

Their study began out of necessity after a 2015 stream / road bank failure along East Brook Road in Walton, which some readers may recall as a DPW road project that took months to complete. In this complex project some 60 cubic yards of knotweed-infested soil was removed from the site to allow for stream and road bank stabilization.The unwanted soil material was trucked to Delaware County’s Solid Waste Management Center, which is also where large volumes of compost are continually created from a mixture of municipal solid waste and biosolids residuals from wastewater treatment
plants.

To produce a safe and marketable finished product, the temperature of the County’s composting process is maintained high enough kill pathogenic bacteria in biosolids as well as any weed seeds from plants. Knowing this, Ms. McIntyre and Mr. Day decided to try completely enclosing the infested soil with layers of compost in an outdoor setting. By the time the trucks stopped rolling and the dust settled, a 20-ft by 200-ft long pile was created of compost-encapsulated soil.

For the rest of the details interested readers will need to look for the journal article in the September 2016 issue of Ecological Restoration, at http://er.uwpress.org/content/34/3/184.full.pdf.html. In summary, after four months of treatment all tested samples of knotweed were found to be lifeless. By its second growing season, the original pile subsided or shrunk in size as the compost oxidized and stabilized, yet not a single knotweed plant has sprouted from it.

This study offers hope for improved Japanese knotweed management and a new avenue of research for its control in the field. It also shows how local efforts towards watershed management continue to pay dividends within and beyond the borders of Delaware County.

L. Day, J. Rall, S. McIntyre and C. Terrance. 2009. Japanese Knotweed Composting Feasibility Study, Delaware County (New York). Ecological Restoration, Vol. 27, Number 4, Pages 377-379.

Abstract

This project investigated the possibility of using a municipal solid waste co-composting facility in Delaware County, NY as a means to safely dispose of “Japanese knotweed” (Polygonum cuspidatum). Live portions of mature knotweed stems, leaves, roots and crowns were subjected to conditions within the composting process by using sentinels to contain and allow retrieval of samples from active piles of compost. Samples were subsequently removed from sentinels, planted in pots containing a peat-based growing medium and placed in growth chambers for 30 days. Treatment of three days or more at sustained temperatures >131° F was adequate to kill all samples in the sentinels; moist heat treatment alone for three days between 125° and 131° F seemed equally effective. Results suggest that introducing minor amounts of Japanese knotweed into the present composting process, which currently produces 30,000 tons of finished product annually, may be a preferred disposal option.

L. Day, 2004. Septic Systems as Potential Pollution Sources in the Cannonsville Reservoir Watershed, New York. Journal of Environmental Quality, volume 33, pages 1989–1996.

Abstract

Onsite septic systems require appropriate soil characteristics in order to provide effective wastewater treatment. The objective of this study was to evaluate siting practices and treatment efficacy of onsite septic systems within the Cannonsville Reservoir watershed (115900 ha) in the state of New York. Using digital soil survey data, a database of onsite conditions was developed from over 1100 existing septic system siting records. Soil map units were grouped into four classes based on their suitability to meet common septic system design criteria. A geographic information system was found to be a useful tool for assessment and visual display of septic system and landscape information. Geographic information system analysis indicated that while 80% of soils in the watershed were found to have characteristics that interfere with septic system function, 69% of septic systems installed were of designs suited for soils with no or few restrictive parameters. Since the designs of many septic systems have relied heavily on horizontal distance to streams (mean 130 m) to provide adequate treatment, potential failures would lead to discharge of compounds of environmental concern, such as phosphorus, with public health implications. The results imply that many septic systems functioning in the watershed are in need of design improvements.

[For a copy of the complete paper, contact the author at: larry-day@dcswcd.org]

Unpublished studies:

Monitoring the potential for subsurface phosphorus delivery to streams in the Cannonsville Reservoir watershed. L. Day and S. Pacenka

Abstract for presentation given by L. Day, DCSWCD Soil and Groundwater Specialist, at the 2006 NYC Watershed Conference, Fishkill, NY, September 20, 2006. Steven Pacenka was employed at the Water Resources Institute at Cornell University at the time of this study.

In the Cannonsville Reservoir basin, the prevalent shallow soils overlying fragipan subsoils combined with limited field evidence and modeling calculations suggest the potential for phosphorus to be conveyed by sub-surface drainage to streams, and thence to the reservoir. Calibration of terrestrial non-point source water quality models has yielded coefficients that indicate that up to one third of dissolved phosphorus arriving at the reservoir might be attributed to groundwater. This project evaluated different land uses to determine if groundwater P-loadings to streams can be substantiated. Five study sites were chosen in the Cannonsville basin based on representative land use (forested, agricultural and residential), soil parent material and landscape position (upland or lowland). Groundwater was sampled ~monthly from relatively shallow wells (~1 to 5 meters deep) in unconsolidated deposits across a number of seasons. A long-term forested upland site was used to represent “background” levels of total dissolved phosphorus (TDP), which ranged from about 1 to 15 µg/L. Preliminary results indicate that total dissolved P levels in groundwater at some sites is significantly above these levels. Samples downgradient from actively farmed fields in upland glacial till soils had TDP levels only slightly greater than background, while greater values tended to occur from shallow wells in more porous, gravelly soils in lowland settings.

A copy of the presentation using preliminary findings is available here.

A copy of the final technical report, dated February, 2007 is available here.

Hydrogeologic Characteristics of an Upgradient Portion of the Solid Waste Management Center, Delaware County, New York. L. Day

Abstract

This study evaluated the relatively deep (bedrock) aquifer on property that is hydrologically upgradient from the Delaware County Solid Waste Management Center. A drinking water well that was installed on a former dairy farm, in addition to newly-installed monitor wells, allowed investigations of aquifer characteristics and quality of groundwater.

An electrical resistivity survey of the study area showed clear trends of low resistivity near the barn, with resistivity increasing downgradient. Well driller's logs indicate that, based on soil materials alone, the resistivity trends should be reversed. The data indicate that pollution originating from past agricultural practices, especially manure handling, has caused the low resistivity values near the barn. Contaminant plumes appear to be following the groundwater contour downgradient and towards monitor wells lS and lD.

A monitor well was installed nearby and the drinking water well was pumped for about 72 hours. Calculations from field measurements show that the bedrock aquifer is unconfined, has a permeability of 2.72 x l0-5 ft/sec, T = 3.35 x 10-3 ft2/sec, and S = 0.097. A computer model (SCAM) gave somewhat different results than the field tests; the aquifer is unconfined, K = 1.3 x 10-6 ft/sec, T = 1.6 x 10-4 ft2/sec, and specific yield = 0.018. The results of the computer model seem more reasonable and should be assumed correct until further field studies indicate otherwise.

Water samples taken from the pumping well at selected time intervals during the aquifer test were analyzed for basic chemical characteristics. Changes in water chemistry occurred throughout the 72-hour test, even after purging 118.5 well volumes. The trend of increasing levels of C1-, Na+ and HCO3- during pumping imply that the source of these ions is naturally occurring and is from within the bedrock aquifer itself, not a localized contaminant plume. The elevated molar ratio of sodium to chloride indicates that additional sodium is coming from some source other than NaCl. Since HCO3- levels were also increasing, the additional sodium may be in the form of sodium bicarbonate.

The trend of decreasing NO3- / NO2- implies that there is a localized plume near the well, likely from former agricultural activities. These findings corroborate the results of the electrical resistivity survey. Negative saturation indices and increasing dissolved oxygen levels indicate that waters were being mixed with those of the overlying sand and gravel aquifer.

A copy of the complete document is available at the SUNY Oneonta campus, Milne Library.