Data-Driven Viewpoints: An Example of a Sub-Watershed Under Stress and Why I Know It

by Brian T Lynch, MSW

I'm writing a series of articles this summer about freshwater resources in the New Jersey Highlands to emphasize the role we all have in preserving the abundance and purity of the waters around us. Two-thirds of New Jersey's drinking water comes from the Highlands. This article focuses on a local level. What I can say about the quality of surface waters in my community, and why I know about it, should serve as a model of environmental awareness to which lake communities and towns throughout the Highlands should aspire. The combination of citizen volunteers, scientists, activists, and advocates organized by the Raritan Headwaters Association (RHA) creates an unprecedented public awareness of the natural habitat in the Raritan watershed that residents in other watersheds may lack.

To begin, all of the drinking water in my hometown of Mine Hill comes from underground aquifers beneath the Succasunna plains. The quality of this water always meets or exceeds state standards. It's good water. But over time, and especially in the past few years, the quality of surface waters in our community has declined. This is a big deal because surface water from the Highlands meets the water needs of nearly half the state. It also matters because surface water infiltrates the ground to recharge aquifers below. The quality of surface waters will eventually influence the quality of the groundwater below.

Lamington tributary upstream near
Canfield Avenue in Mine Hill

Mine Hill straddles a ridge between two drainage basins, one for the Rockaway River, the other for the Raritan. I can't tell you how well we are protecting the surface water flowing into the Rockaway River's tributaries on one side of town. I just don't know. I can tell you a good deal about the surface waters flowing West from the headwaters of Lamington and Black River which originate in this sub-watershed in which I live. Together these tributaries form the North Branch of the Raritan River.

The land area where rain falls on the Western half of my town drains into the Lamington tributary in Mine Hill between Canfield Avenue and Sunset Pond (yes, the beach) where it empties.

Freshwater Lampreys in the Black
River near the Great Spring

The Black River originates in a remarkably prolific area of springs at the Southern tip of the former Hercules Powder Company land in an area the Lenape natives called the "Great Spring." The Great Spring is in the Kenvil section of Roxbury Township. This Northernmost section of the Black River also empties into Sunset Pond, which is actually the remains of a very large sandpit. The entire area, known locally as the "flats" has a deep underlayer of sand that allows water to percolate through to other abandoned sandpits, which now serve as ponds for commercial and residential development. The only natural open water is Black River Pond which receives most of its water from the Great Spring and the Lamington tributary. All of the land areas that drain down to Black River Pond constitute the sub-watershed of which I focus here. It's the watershed in which I perform most of my volunteer work for the RHA.

To better understand the stream monitoring role that the RHA plays in the Raritan River Basin I am including a sidebar from their Website. They can explain themselves better than I can. There are two stream monitoring sites in our sub-watershed, one in Mine Hill and one in Kenvil. A third monitoring site just south of Black River Pond is the upper boundary of another sub-watershed area. The entire Raritan basin is divided up this way to help pinpoint specific areas that may need attention. Our sub-watershed is one of those areas.

Each year, the RHA publishes its extensive stream monitoring and laboratory analysis results in an annual "report card." The scientific methodologies and jargon used to quantify factors affecting water quality can be daunting to non-scientists. The RHA Report Card assigns letter grades or pass/fail grades to these numbers so everyone can understand the findings. These findings are seldom reported in local newspapers, but they are publicly available on the RHA Website. The monitoring and testing results for our sub-watershed was given it a failing grade over the past few years. We who live and work here can and must do better. Fortunately, there are lots of simple, inexpensive things we can do as a town and as individuals to improve our water quality, but the first step is to acknowledge that there are problems to solve.

RHA REPORT CARD

Below are a series of screenshots of the RHA Report Card data taken from their website.

The first screenshot below is the RHA 2020 report on the overall High Gradient Macro-invertebrate Index (HGMI) for the entire Raritan basin. These are findings gleaned from collected samples of the small macroinvertebrates (insect larva, mollusks, worms, etc.) that live in stream beds. The more diversity and abundance of creatures, especially of the pollution-sensitive species, the better. An explanation is given this and all the factors being graded. The Raritan Basin as a whole scored a "C" letter grade, but each sub-watershed is separately graded. Sub-watersheds that are shaded in blue passed on this measure while those shaded in brown failed. The map depicted here has been zoomed in to show the headwaters sub-watersheds for the North Branch (right) and South Branch (left) of the Raritan River. The North Branch where I live failed.

This next screenshot reports on the Ortho Phosphorous Indicator related to the nutrient load in the streams. This screen, and the rest of the Report Card screenshots below, are specific to the North Branch headwaters watershed in which I live. You can see that this area and the adjacent South Branch headwaters watershed failed. An explanation of the factors is below under the letter grade.

The next factor on the Report Card pictured below is the Specific Conductance Indicator, which generally relates to the amount of road salt that washes into the streams. These are the three indicators on which my sub-watershed failed. The North Branch headwaters sub-watershed received an overall failing grade as well when all the indicators are combined.

The next three factors are all indicators on which the local sub-watershed area passed. These indicators are Stream Temperature, Dissolved Oxygen, and Ph.

As mentioned earlier, the overall score for this sub-watershed was an "F", but this detailed analysis suggests where efforts can be focused to correct specific problems. This in-depth analysis is not commonly available throughout the rest of the Highlands. And by monitoring these streams consistently over time, the Raritan Headwaters Association is able to analyze and report on long-term trends in water quality.

The next screenshot is not from the Report Card, but from a draft report on long-term trends. The data is from 1999 to 2017 and it is aggregated to four large areas in the Raritan Basin. The screenshot below is for the North Branch of the Raritan River basin located within the Highland Region.

The rising lengths of the orange bars at the bottom from left to right, and the emergence of red shaded bars on the right, reveal the steady and growing decline in surface water quality over time. It is evidence that river basins in the Highlands are increasing under stress. The local problem in my sub-watershed is part of a much larger pattern of declining habitat and water quality that must be addressed.

BROADER VIEW

We all live in a watershed. Better knowledge and awareness of the natural environment around us is key to preserving the fresh water on which all life on land depends. What the Raritan Headwaters Association is doing to monitor and track the health of the waters and habitat in the Raritan basin can and should be duplicated elsewhere throughout the New Jersey Highlands.

I have a special affinity for Lake Hopatcong where I grew up. I was deeply disturbed by the HAB crisis that shut down the lake a few years back. We all know that there are big projects around the lake that need to be undertaken to improve stormwater management and expand sewer service (to name a few), but there are so many smaller actions that individual homeowners and business people can take which collectively would greatly improve the lake water.

The Lake Hopatcong Foundation is working diligently on water quality and habitat issues around the lake. It has many helpful suggestions for lake residents to consider on its Website. But, there are also eighteen freshwater inlets around the lake. I visited and photographed each of them in 2017 and learned a lot in doing so. Some of these streams flow out of extensive and beautiful wetlands. Some flow through smaller lake communities. Most of the streams and feeder lakes serve as conduits for storm drain outfalls. From my perspective, all of these streams should be continuously monitored in much the same way as are the tributaries in the Raritan basin. Consistent scientific monitoring of the waters and habitat surrounding these tributaries before they flow into Lake Hopatcong would be an important advance towards improving the environmental health of the lake's drainage basin.

And of course, water from Lake Hopatcong flows into the Muscanectong River, which flows into the Delaware River. It's all connected. We are all connected by the rain that falls here in the Highlands. We must be responsible partners in maintaining the health of this vital and environmentally sensitive, and beautiful region.

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Data-Driven Viewpoints

Sunday, July 25, 2021

An Example of a Sub-Watershed Under Stress and Why I Know It

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