Posts Tagged ‘Nine Mile Run


by John Lavaccare, Communications Intern, Nine Mile Run Watershed Association

Earlier this month I spent the day on an electrofishing trip through the Nine Mile Run stream led by two instructors from Duquesne University, Dr. Brady Porter and Dr. Beth Dakin. Electrofishing is an activity where scientists use an electric pole to temporarily stun fish, catalog the species and sizes of fish found, then release the fish back into the water. Electrofishing helps us understand the quality and health of the Nine Mile Run stream by learning more about the variety of fish that live in the stream.

Along with Dr. Porter and Dr. Dakin, there were 7 students on the trip from Duquesne University, Chatham University, and the University of Pittsburgh. The students included undergraduates, graduate students, and a postgraduate student. Some were there as part of a class assignment; Dr. Dakin said the assignment helps students understand “the amount of effort that lets us know things about ecosystems and fish communities”.

Others were there because they simply wanted to take part in the electrofishing activities. The students had various interests and knowledge levels about marine biology and ecology, and it seemed like everyone had an enjoyable and enriching experience.

One local community member joined us on the trip: Mike Koryak, a former member of the U.S. Army Corps of Engineers who retired in 2004, and has served on the NMR Monitoring Committee since 2006. Mike said he was part of the original inspection project at this site, and he marveled at the progress the stream has made since the restoration project was completed in 2006.

“In so many ways, it’s been dramatic,” Mike said of NMR’s transformation. “It’s a long time coming.”

We started our electrofishing day in the lower part of the Nine Mile Run stream, near where it meets the Monongahela River. The process goes something like this: The person with the electric rod has a charge emanating from both the front of their pole and from a “rat tail” that hangs from the box on their back. While this is happening, participants with nets examine the areas where the electric rod and rat tail have been, collecting the stunned fish from the water and putting them in buckets to be sorted and counted later. If the stream is still electrified (which it is briefly after the rod has passed through it), they have to be careful not to get the exposed skin on their hands in the water. In addition, electrofishing participants wear waders, which are akin to rubber overalls connected to boots. They help protect the participants’ legs from water and from electrocution, so any holes in them could prove troublesome.

This first part of the process involved separating fish by species into buckets. Artificial bubbles were used to keep the water in the buckets oxygenated. In all, 11 species were catalogued during the first portion of the electrofishing process. Dr. Porter and Dr. Dakin were able to classify the fish on sight based on their spots, mouth placement, eyes, and other features. Cullen Hanes, an electrofishing participant and undergraduate student at Chatham who is interested in herpetology, or the study of amphibians, said he hopes to be able to identify amphibians in the way Dr. Porter can identify fish. “I tried to listen to him as best I could,” Cullen said. “I still, like, had to keep asking what type of fish this is.”

After the fish were sorted successfully, they needed to be counted, measured, and weighed before being released. In the first part of the stream, spotfin shiners (like the one above) were abundant, and the electrofishing team counted 199 of them in this portion of the stream. After the event, Dr. Porter said that spotfin shiners are a “pioneering species”, which means that it’s one of the first types of fish to break into more polluted areas. He said surveys like this one allow scientists to understand which species are pioneers.

This rainbow darter was found in the upper part of the NMR stream area we surveyed.

Though we were most interested in the fish, there were various other types of wildlife to be found about the stream, including two caterpillars like this, a crawfish, and even a bullfrog.

In all, Mike and Dr. Porter felt that this survey found fewer fish in the stream than in past years. They theorized that this might be because of the construction for the new bridge to the Duck Hollow neighborhood, which has caused the stream to be culverted underneath a gravel bridge in the middle of the area we surveyed. Dr. Porter theorized that transient species—those that come into the Nine Mile Run stream through the Monongahela River—are having difficulties making their way through the culverts to the upper part of the stream. Nine Mile Run Watershed Association has been and will continue to monitor the effects of this construction project.


If you’ve taken a walk in lower Frick Park recently, you’ve undoubtedly noticed the unusual amount of trash and debris scattered around the flood plain and dangling from trees and shrubs, as well as some significant erosion of the walking trails.  I’ve been working with the Watershed Association for more than 11 years, and I can honestly say conditions are the worst I’ve ever seen in and around the restored stream, with the possible exception of June 18, 2009, the day after a particularly intense storm system rolled through. This time there is not just a single storm system to blame.  Instead, what you are seeing is a graphic manifestation of how climate change is impacting our region.

For years the accepted average amount of annual rainfall in Pittsburgh was 37.7 inches – and if you ask Google, that is still what you will find. But in 2017 we had 40.6 inches, and last year the total was an extraordinary 57.8 inches. This year, the rain gauge at the bottom of Nine Mile Run had already recorded 37.1 inches by July 31st. So we will almost certainly exceed 2017’s total this year, and may come close to another record year.   Not only are the totals higher, but the way the rain arrives has changed as well. Only a few years ago, a summer thunderstorm “tropical downpour’ would last for just a few minutes, and then it would gradually taper off to a more moderate rate, or even stop altogether. Now we frequently experience intense downpours that last for 30 or 40 minutes, or more. 

Blue shopping bags dangle from branches along the stream

What’s going on here? Well, it’s pretty simple. Warmer air holds more water vapor, and eventually that will find its way to earth as snow, sleet, rain, or hail. And as anyone who hasn’t been living in a cave knows by now, our temperatures are getting warmer, both here in Pennsylvania and globally. Worldwide, the five warmest years on record were the past five years — and the 20 warmest occurred over the past 22. The warmest year on record for the earth’s oceans was 2018.  Every time that a weather reporter uses words like “record-breaking”, or “unprecedented” to describe a weather event or disaster, that should be followed by an explanation that these are exactly the kinds of events that climate scientists have predicted for decades and that we should expect as the earth warms.

As we explain at all of our stream sweeps, since much of the watershed has separated storm sewers, heavy rains carry any trash on the streets into the storm sewers and directly into Nine Mile Run, during major rain events, the stream spreads out across the flood plain, which is exactly what was intended in the re-design of the stream when it was restored between 2003 and 2006. But this year’s storms have carried more trash, and deposited it over a wider area, than ever before.  While it isn’t safe to be in the middle of the valley during one of these prolonged intense storms, you can find out later how high the water got by just looking at where the plastic bags and other debris are hanging from the trees. 

Toilet paper and trash bags hang from tree branches across the flood plain

One of our core missions here at the Watershed Association is to steward the NMR restoration area. In addition to our annual Spring and Fall Stream Sweeps, this year we will be scheduling some additional clean-ups to deal with the “unprecedented” amount of trash we are facing.  Follow us on social media for announcements of when these will be happening if you’d like to help out. We’ll also keep working on better stormwater management solutions in the upper watershed communities to try to reduce the overall burden of flooding that the stream now faces on a regular basis. If you already have a rain barrel or rain garden, or a street tree in front of your house, THANK YOU!! If not, and you are interested in getting involved to help solve the problem, give us a call.


Hello! My name is John, and I am a junior environmental science student at the University of Pittsburgh. This past semester, I have been working on an interactive display of the restoration project which reconfigured Nine Mile Run and parts of Frick Park.

I wanted to get involved with Nine Mile Run Watershed Association (NMRWA) because I was inspired by how dedicated and passionate this group is about improving urban water quality. This organization seems to me like part of a greater recommitment by people around Pittsburgh towards restoring our city’s natural beauty.

Conservation has always been important to me, and being an Eastern PA native I grew up enjoying preserved land areas like Stroud Preserve. When I started going to school in Pittsburgh, Frick Park quickly became one of my favorite local spots for mountain biking. Since then I’ve rode over and next to Nine Mile Run countless times, enjoying this oasis of nature in the urban setting.

Clean water has been an interest of mine ever since I moved to Pittsburgh and learned of the challenges urban streams are facing. Also, this past summer I spent much of my time wading in streams while interning for the PA Department of Environmental Protection. These previous experiences blended perfectly in my work with NMRWA, where I could help display innovative solutions to issues of urban stream health.

Using ArcGIS, and past reports on the restoration project, I created maps displaying impervious cover, culvert systems, stream channel reconfiguration, and wetland creation and modification. Along with my maps, the display includes historical photos of the creation of Pittsburgh’s sewer systems from over 85 years ago!

I am grateful to have learned so much about the restoration project in Nine Mile Run, and to be able to learn from leaders in sustainable development. One important takeaway from my experience is that stewardship is never over, and I look forward to continuing to be a part of keeping Nine Mile Run healthy and beautiful!

My ArcGIS story map will be up on the Nine Mile Run website sometime soon, so be on the lookout!


This guest post was written by Rob Rossi, a graduate student in the department of Geology and Environmental Science at the University of Pittsburgh. He was a graduate summer intern of NMRWA in 2015.

Road salt is a common part of winter for many Pittsburgh residents.  In Pennsylvania, more than 840,000 tons of road salt (sodium chloride, or table salt) were applied to roadways between 2009 and 2014.  Although it helps keep our roads and sidewalks ice and snow free, road salt has unintended consequences.  Many people are familiar with the ever annoying winter problems of salt stained clothing or shoes/boots, but the environmental effects of road salt are less obvious.  Road salt can have numerous negative effects on the environment, such as increased fresh water and soil salinity, and less obvious effects, such as increased time necessary for rain to soak into the soil.  Additionally, when road salt dissolves in highway runoff, these waters have high total dissolved solids (TDS), which can flush roadside soil metals from clay particles  (see animated Figure 1).  Metals flushed by these reactions can include plant nutrients (e.g., potassium, calcium, magnesium) or toxic trace metals (e.g., arsenic, lead, cadmium).

Road salt exchange gif

Figure 1. Animation of a cation exchange reaction. Potassium (K), calcium (Ca), and magnesium (Mg) ions bound to soil clay particles are exchanged by sodium (Na) ions in solution. Mobilized metals are then released into the soil water, and ultimately the ground or surface water.

Road Salt Study in Nine Mile Run

Lysimeter Working

Figure 2. Lysimeters are plastic tubes with a ceramic cup. To collect a soil water sample, a scientist applies a vacuum (arrow) and the lysimeter sucks up soil water (dashed lines) like a straw.

Rob Rossi, a graduate student in the Department of Geology and Environmental Science at the University of Pittsburgh, has been researching the effects of road salt on roadside soils in Nine Mile Run.  Specifically, Rob has been analyzing soil and soil water chemistry in samples collected from three roadside soil water sampler “nests”.  Each nest is a group of four lysimeters which behave much like giant straws, sucking up soil water samples when a vacuum is applied to the end of the soil water sampler (see Figure 2).  The lysimeters collect soil water at roughly 6, 12, 24, and 36 inch depths along a hill slope perpendicular to I-376.

In the soil samples, soil sodium concentrations are highest in soils collected from near the road.  Soil sodium concentrations decrease with distance from the roadway, approaching values observed in the local bedrock (see Figure 3).  One theory is that high sodium concentrations can be attributed to the minerals breaking down in the bedrock but because sodium concentrations in roadside soils are much higher than sodium concentrations found in the bedrock, minerals in the bedrock breaking down is likely not what inputs sodium to these soils.  Instead, the application of road salt to I-376 is likely causing high sodium concentrations in roadside soils.

Sodium concentration chart

Figure 3. Sodium concentrations in the sampled top (black), mid (red), and bottom (grey) hillslope soils. The vertical dashed line indicates the average sodium concentration in local bedrock. Parts per million (ppm) is a measurement scientists use to describe the concentration of an element. In other words, if a bucket holding a total of 1 million marbles contained 100 ppm of blue marbles, 100 of those 1 million marbles would be blue marbles.

Sodium concentrations in sampled soil waters peak at different times throughout the year relative to the location along the hillslope (see Figure 4).  In particular, the earliest peaks in soil water sodium concentrations occur in the top hillslope soil waters in late February/early March in the intermediate depth (39 and 61 cm depth) soil waters.  Additionally, soil water samples from the deepest top hillslope nest have, in general, the highest sodium concentration.  While sodium concentrations spike in soil waters collected from all depths of the top hillslope nest station, soil water sodium concentrations peak only in deeper soil waters of the mid hillslope nest.  Moreover, the peak in soil water sodium concentrations at the mid hillslope nest do not peak at the same time as when soil water sodium concentrations peak at the top hillslope nest.


Figure 4. Sodium concentrations in top (a), mid (b), and bottom (c) hillslope soil waters collected between October 2013 and November 2014. The light blue box indicates the time of the year when road salt is not applied to roadways.

These patterns in soil water sodium concentrations suggest that the way soil water flows in roadside soils influences the movement of sodium through these soils.  Specifically, because the deeper top hillslope lysimeters (i.e., 12, 24, and 36 inch) peak before the shallowest (i.e., 6 inch) lysimeter, high TDS waters likely interact with deeper soils first.  High TDS runoff from the highway is often observed to enter the soil column via infiltration (i.e., water percolating downwards through the soil), which produces a peak in sodium concentrations in the shallowest soil waters first.  However, because this pattern in soil water sodium concentrations is not observed in samples collected from the Nine Mile Run transect, sodium is potentially transported to deeper soils via lateral flow originating from leaking highway drains and water flow between bedrock layers.

Previous scientific studies have observed that sodium loadings to soils persist beyond the period when road salt is applied to roadways, and this relationship is also apparent at this study site.  Specifically, sodium persists as slow moving wave, where peaks in top hillslope soil water sodium concentrations occur within a month of when road salting ends, and peaks in soil water sodium concentrations at the mid and bottom hillslope stations occur later in the year.  Thus, the distance from the roadside affects when soil water sodium concentrations will peak, suggesting that sodium is relatively slowly released from roadside soils throughout the spring and summer.

How does road salt affect the water quality of Nine Mile Run?

The results of this study suggest that sodium and metals are continually flushed to stream waters throughout the year. When sodium levels are high, the ecosystem cannot physiologically maintain a salt balance, which affects aquatic organisms living in the stream – particularly plants and animals that are not adapted to high concentrations of ions, and therefore cannot regulate the water and salt content within their cells. This stress can change the diversity of species within the ecosystem. The increased metal loading could impair the stream ecosystem, negatively impacting aquatic life such as fish.  Some metals may be either beneficial or toxic, depending on their concentration. The primary mechanism for toxicity to organisms that live in streams is by absorption or uptake across the gills. The metals that are most toxic to aquatic organisms are Copper, Iron, Cadmium, Zinc, Mercury, and Lead.

I-376 Sodium runoff model

Figure 5. A conceptual model of how sodium travels through the hill slope soils next to I-376. The color of the arrows indicates the relative timing of when sodium is transported via this flowpath. Blue occurs in mid to late February, dark grey in early March, orange in early May, and red in early August.

Thus, it is likely that road salt application impacts soils down the hillside of I-376, and that the negative impacts of road salt application are not limited to the winter and early spring.


Bright and early on a crisp Sunday morning, Jared Manzo, NMRWA’s GreenLinks Coordinator, guided participants on a tree identification walk through the lower section of Nine Mile Run. With rubber boots required, the first half of the walk traveled in or along the stream itself where no official trail exists.

Event participants crossing the stream. Jared Manzo talking to explaining leaf structure of a Boxelder.

Several species of trees were highlighted along the stream such as American sycamore, black willow, honey locust, silver maple, boxelder, common hackberry, and hardy catalpa. In a small patch of changing sugar maple, Jared explained what triggers dormancy in trees, the chemicals that produce fall color, and why leaves change color at all with the onset of dormancy.

A sugar maple slowly turning color.

Before moving back up to the Nine Mile Run Trail, Maranda Nemeth, NMRWA’s Restoration Stewardship Coordinator, took a moment to discuss a project along the run to allow fish to move further up stream. We returned to our starting point on Commercial Avenue by jumping onto the Nine Mile Run Trail. Some interesting species noted along the trail were staghorn sumac, black birch, sassafras, black gum, and bitternut hickory.

Overall, twenty-one tree species were identified. Tree identification focused on the most recognizable features of a given species to help distinguish it in the future. Leaf arrangement, simple leaves versus compound leaves, and the definition of a twig were discussed as well. Hot apple cider and muffins were great snacks given the chillier than usual October morning.

A medley of leaves fallen in Nine Mile Run.

If you are interested in tree identification, look out for walks in 2016 with NMRWA or Tree Pittsburgh! You can get started yourself by getting a guide such as Tree Finder: A Manual for Identification of Trees by Their Leaves or downloading Virginia Tech Tree ID app for your iPhone or Android device.

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