D&R Canal – Six-Mile Run Culvert Dye Testing
May 20, 2020
The New Jersey Water Supply Authority (“Authority”) operates and manages the Transmission Complex of the D&R Canal as a water supply facility. In keeping with its obligation to maintain a dependable supply of water to central New Jersey, the Authority is preparing to undertake rehabilitation of the “Six-Mile Run Culvert”, which dates back to the original construction of the Canal in the 1830s.
The Six-Mile Run Culvert is located in Franklin Township, Somerset County at Canal Station 2298+17, approximately 1,000 feet south of Blackwells Mills Road. It carries the Six-Mile Run (stream) under Canal Road, the Canal, and the multi-use path. The inlet and outlet ends of the culvert have been repaired several times, but there are no records of rehabilitation of the interior culvert barrels.
The Authority has contracted with Johnson, Mirmiran, & Thompson (“JMT”) for the engineering design for full rehabilitation of the culvert. The design will be approved by the State Historic Preservation Office, as the structure is part of the original fabric of historic appurtenant structures along the Canal.
Depending on weather conditions, Authority’s consulting engineers will soon conduct dye testing in the vicinity of the culvert to assess its condition in the near future. Dye will be added to the Canal just upstream of the culvert and it will be visible for some distance in the Canal and possibly in Six Mile Run. For the day of the test, Authority staff will attempt to slow the flow of the Canal in the area of the culvert to force a more prolonged period of time that the dye stays over the culvert. It is anticipated that the test will take place over a period of one day. Authority staff will provide a second notice at least 48 hours prior to the test. There will be no interruption in the supply of water to all purveyors on the Canal.
The dye that will be used is manufactured by BrightDyes (http://www.brightdyes.com/). The testing will utilize FLT Yellow/Green liquid, which appears yellow/green to the naked eye. It is certified by NSF International to ANSI/NSF Standard 60 for use in drinking water. The dyes are safe for use in all public water supply systems, are biodegradable, photodegradable, and are non-toxic/non-harmful to aquatic life.
The Canal passes between 80 and 100 million gallons per day (MGD) on a normal day. Canal flow will be adjusted to as slow as practical for the dye test. The plan is to utilize an amount of dye of approximately 1 gallon, depending on conditions at the time of application. Given those quantities, only 5% of the Canal water will be showing the color at each application, when returned to full flow. The coloring completely dissipates from exposure to sunlight over a period of two to three days. In this case however, due to the size of the Canal and the small areas of water to which the dye is being applied, visual signs of the coloration will likely dissipate in less than 6 hours.
If you have any questions or require further information, please contact Paul Harenberg, Authority Project Engineer, at pharenberg@njwsa.org
The New Jersey Water Supply Authority (“Authority”) operates and manages the Transmission Complex of the D&R Canal as a water supply facility. In keeping with its obligation to maintain a dependable supply of water to central New Jersey, the Authority is preparing to undertake rehabilitation of the “Six-Mile Run Culvert”, which dates back to the original construction of the Canal in the 1830s.
The Six-Mile Run Culvert is located in Franklin Township, Somerset County at Canal Station 2298+17, approximately 1,000 feet south of Blackwells Mills Road. It carries the Six-Mile Run (stream) under Canal Road, the Canal, and the multi-use path. The inlet and outlet ends of the culvert have been repaired several times, but there are no records of rehabilitation of the interior culvert barrels.
The Authority has contracted with Johnson, Mirmiran, & Thompson (“JMT”) for the engineering design for full rehabilitation of the culvert. The design will be approved by the State Historic Preservation Office, as the structure is part of the original fabric of historic appurtenant structures along the Canal.
Depending on weather conditions, Authority’s consulting engineers will soon conduct dye testing in the vicinity of the culvert to assess its condition in the near future. Dye will be added to the Canal just upstream of the culvert and it will be visible for some distance in the Canal and possibly in Six Mile Run. For the day of the test, Authority staff will attempt to slow the flow of the Canal in the area of the culvert to force a more prolonged period of time that the dye stays over the culvert. It is anticipated that the test will take place over a period of one day. Authority staff will provide a second notice at least 48 hours prior to the test. There will be no interruption in the supply of water to all purveyors on the Canal.
The dye that will be used is manufactured by BrightDyes (http://www.brightdyes.com/). The testing will utilize FLT Yellow/Green liquid, which appears yellow/green to the naked eye. It is certified by NSF International to ANSI/NSF Standard 60 for use in drinking water. The dyes are safe for use in all public water supply systems, are biodegradable, photodegradable, and are non-toxic/non-harmful to aquatic life.
The Canal passes between 80 and 100 million gallons per day (MGD) on a normal day. Canal flow will be adjusted to as slow as practical for the dye test. The plan is to utilize an amount of dye of approximately 1 gallon, depending on conditions at the time of application. Given those quantities, only 5% of the Canal water will be showing the color at each application, when returned to full flow. The coloring completely dissipates from exposure to sunlight over a period of two to three days. In this case however, due to the size of the Canal and the small areas of water to which the dye is being applied, visual signs of the coloration will likely dissipate in less than 6 hours.
If you have any questions or require further information, please contact Paul Harenberg, Authority Project Engineer, at pharenberg@njwsa.org
