Groundwater and Wells

The major source of water in Mountain Lakes is an aquifer of considerable depth (about 200’ – 300’) running along Route 46 east of the Boulevard and nearly parallel to Pocono Road west of the Boulevard. Near the western boundary of the Borough the channel forks, one fork running west toward St. Francis Health Resort, Denville, and the other running north through the Rockaway River Country Club and up the Rockaway Valley. Current engineering studies indicate that it is highly probable that future municipal water supply will draw from this aquifer. Extensive material on the delineation of this and other relevant regional aquifers can be found in the Geraghty and Miller (1978) and Geonics (1979) studies.

Virtually all the Borough water supplies come from this aquifer, from a wellfield in the Rockaway Valley and from a well on the south side of Route 46 east of the Boulevard. Residential water is stored in two tanks with a capacity of 1.5MM gallons and the Borough pumps roughly 750K gallons a day. The NJDEP has established annual and monthly groundwater usage allotments to protect regional water resources.  In 2005 and 2006 the Borough exceeded its state-mandated water allocation for two months causing a state-mandated 5 year new connection stop.

Well locations are important to an ERI because they identify points where surface pollutants may reach the groundwater more easily. Known contaminated sites on Rte 46 which could impact groundwater are B&V Tailoring and Cleaning and the Hess Station.  In fact, Well #5 was detected to have low but measurable levels of PCE in 1991-1997 with 0.4-0.9 parts per billion detected.  Beginning in 1997 PCE was found to be in excess of NJ State limits ranging from 1.2 -1.5 ppb.  An air stripper was subsequently installed on this well in 2000 and the water quality now consistently meets all State requirements.

In an area such as Mountain Lakes where groundwater is the primary source of supply, maintaining the wells and groundwater quality is critical. At this time, the Borough has no well-head protection ordinances to ensure the future viability of its sole water supply. Work in this direction is made difficult by the fact that to a large extent, the aquifer and its recharge area are located on private land (both developed and undeveloped) with a good percentage of it falling outside Borough boundaries. This mandates a regional approach which is considerably more difficult to achieve.

The information provided in the Water Table Map and Table 1 is a fairly complete inventory of wells in the Borough. Further investigation at specific sites may reveal additional wells not included here. This information indicates the level of groundwater pollution risks and alerts those involved in planning and site plan review to the problem. Such an understanding of the general difficulty in preventing groundwater pollution is important.

Early settlers prior to 1910 depended upon individual private wells. These wells appear as G, H, I, K, M and O. Buildings after 1910 were tied into a privately-owned water supply system. This was later taken over and improved by the Borough.  Well C dates from this period and is now inactive.  Wells E and F, the other inactive Borough wells, were drilled for test purposes and never used for production.  The currently active Borough wells are A, B and D and two additional wells located on the Rockaway River in Denville at the Rockaway River Country Club.  The remaining wells are privately owned and drilled at various times from the 1920’s through the 1950’s.