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Open Space and Water Quality | Lessons Learned from Three Years of Stream Monitoring

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By Anna Willig, Watershed Conservation Associate and Lauren McGrath, Director of Watershed Protection Program

Since 2018, the Watershed Protection Program has monitored 10 sample sites in the headwaters of the Darby, Crum, and Ridley Creeks (see map). Through visits every four weeks, the Watershed Protection Team has learned that the headwaters are negatively impacted by human activity on the surrounding landscape. All of the sample sites surveyed had periods of stressful conditions, harming stream life. Stressors included very warm temperatures in the summer, road salts in the winter, and fertilizers throughout the year. However, sample sites with the most open space in their watersheds had the best water quality, indicating that open space preservation is one of the most effective ways to protect and improve water quality in our area.

Water temperature is a critical factor for understanding water quality within a stream system. In Pennsylvania, water temperatures are evaluated based on how they affect trout, which are sensitive to temperature and will not breed or survive if streams are too warm. Water temperature and oxygen levels are tightly linked; cold water can hold the high concentrations of dissolved oxygen needed to support sensitive species, but as water warms, that amount decreases. Figure 1 shows the required temperatures to be considered a Cold Water Fishery — a stream that supports the survival and reproduction of trout — are exceeded at all sites year-round, indicating that streams are too warm to support breeding trout and similarly sensitive organisms and can even reach the point where conditions are stressful for stocked trout during summer heatwaves. These elevated temperatures limit biodiversity at sample sites; only species that tolerate high temperatures can survive and reproduce.

Figure 1. Water temperature at 10 sample sites in the headwaters of the Darby, Crum, and Ridley Creeks from 2018 through 2021. The lines represent maximum allowable temperatures for a Cold Water Fishery (CWF, solid), a Trout Stocked Fishery (TSF, dotted), and a Warm Water Fishery (WWF, dashed) according to PADEP standards. Sampling was paused from April 2020 through December 2020 due to the COVID-19 pandemic.

In addition to monitoring water temperatures, the Watershed Protection Team also analyzed specific conductivity, which is a general measurement of water quality that provides insight into how disturbance on the landscape impacts a waterway. Increases in conductivity occur when road salts, fertilizers, or other pollutants wash from the landscape into the stream. A common cause of increased conductivity in winter months is salt washing off of impervious surfaces — roads, sidewalks parking lots — into waterways. The more impervious surfaces within a watershed, the more opportunity for these contaminants to wash into the streams and increase conductivity.

The Trust’s ongoing study has found that there is a relationship between conductivity and the amount of impervious surface cover in the surrounding watershed. Sample sites in watersheds with the highest percentage of impervious surfaces tend to have the lowest water quality, as indicated by elevated conductivity, while sample sites in watersheds with more open space are the least impaired. Figure 2 shows the relationship between higher conductivity and the amount of impervious surfaces in the watershed. Developing a better understanding of this relationship is critical, as it helps to identify how we can make smart changes in the way we interact with the land to better support the health of the wetlands, streams, and rivers in our region.

Figure 2. Conductivity and impervious surface cover across 10 sample sites in the headwaters of the Darby, Crum, and Ridley Creeks from 2018 through 2021. Boxplots represent specific conductivity and bars represent the percent impervious surface cover of each catchment by area. For each boxplot, the box represents the middle 50% of values and the median. Dots outside of whiskers show values that can be considered outliers.

What can be done to improve water quality in Darby, Crum, and Ridley Creeks?

Based on three years of data, we believe it is important to reduce water temperature and conductivity in local streams to improve habitat and increase biodiversity. One of the most effective ways to accomplish this goal is by planting native plants along streams in riparian areas, the land that borders waterways. Streamside trees and shrubs provide shade, reducing water temperature and increasing dissolved oxygen. Native plants slow and absorb runoff, limiting the amount of pollutants like nutrients and salts that reach the stream, which reduces conductivity. While large scale plantings are important, you do not need to have acres of property to benefit local streams and rivers! Adding native plants to lawns, fields, and gardens goes a long way to improve water quality, even if you do not live alongside
a stream.

Overall, the best tool for protecting and improving the health of our streams is preserving open space, especially in critical habitats like wetlands and riparian areas. Each covered in pavement and will not need road salt or fertilizer applications. Without impervious surfaces, water can infiltrate into the soil and flow through the ground rather than over it, meaning that when it enters the stream, it is cooler and cleaner than if it had run off from a parking lot or road. As a result, water temperatures and conductivity stay down, making streams more hospitable for all types of life.

Not only does protecting open space keep waterways clean for the organisms they house, it also keeps water clean for water sources, and all three creeks — Darby, Crum, and Ridley Creeks — flow into the Delaware River, which provides drinking water for millions of residents. By protecting open space and water quality in the headwaters, we are ensuring that we do not place the burden of cleaning up our pollution on the downstream communities that drink from these waters.

The research conducted by the Watershed Protection Team is ongoing, and a full report will be available this summer.

Plastic Free July Resources

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Watch

  • A Plastic Ocean | You may remember this documentary from our film presentation – it’s now available on Netflix!
  • Plastic Ocean Documentaries | A series of short films highlighting plastic pollution around the world

Read

Shop

Follow

  • Anne-Marie Bonneau | @zerowastechef | Blogger, fermenter, sourdougher
  • Bea Johnson | @zerowastehome | Author of “Zero Waste Home”
  • Kathryn Kellogg | @going.zero.waste | Get great recommendations on DIY replacements for plastic
  • Lauren Singer | @Trashisfortossers | This CEO of plastic free shop demonstrates her zero waste lifestyle

Creek Week: Harmful Algae Blooms

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The arrival of warm weather means summer is coming and peak swimming season is right around the corner. However, when looking for spots to swim, always be mindful of looking at the Harmful Algal Bloom (HAB) index. HAB’s are when algae, blue-green cyanobacteria, densely grows in a body of water making it look green and smell foul. Not only does the water look odd, it actually becomes dangerous due to toxins that the algae secrete. This can cause issues to everything living in or around the contaminated water source, as the toxins are extremely fatal. In freshwater sources, HAB’s will most likely look green to a rusty orange while saltwater blooms can have a vibrant red coloration. There will also be a distinct “rotten” smell that comes from the water which comes from the constant decomposition of the algae and other living beings that have been affected by the blooms (CDC, 2021).

When an instance of HAB occurs in a waterway, there are many immediate concerns that arise for wildlife. The algae grows at the surface of water, which blocks light from reaching the floor where most aquatic plants live and rely on light to make energy. When aquatic plants die, many of the species that use them for food and shelter are negatively impacted and may struggle to survive. Aquatic plants are a large source of oxygen in water, so when HAB’s photosynthesize at the surface, not only do they kill species that add oxygen, but they also use the already lowered supply themselves, which creates a cycle of losing vital oxygen. In addition, the algae itself produces toxins that are fatal to many aquatic species, killing them within days of exposure. These processes all occur simultaneously and are referred to as eutrophication, a surplus of nutrients that leads to overgrowth of plant life and death of animal life (Oxford Languages, 2020).

While these effects of HABs may seem disconnected from human life, the exact opposite is the case. Swimming in water contaminated by HAB’s can have immense health effects on people of all ages, and can even be deadly. Direct exposure to blooms may cause a rash, stomach illness, respiratory illness or neurological effects (EPA, 2019). In young children, ingestion can lead to poisoning that requires immediate medical attention. A commonly overlooked aspect of the effects of HABs are their impact on dogs and pets. Before allowing a dog to drink from a waterway, be sure to check for the telltale signs of HABs, as a dog can be poisoned and die within a matter of hours. The signs of algal poisoning in dogs are: lethargy, panting, diarrhea, seizures, vomiting or respiratory failure (ASPCA, 2019). Also be aware of rinsing your dog’s fur after contact with contaminated water as the toxins can stick to fur and they may be poisoned from grooming themselves. Although there are dangerous impacts to human health, there is little prevention that can be done to protect waterways.  The exact root cause of HABs is not known, so the best way to protect yourself is to be knowledgeable on the signs of contaminated water. The best supported theories about the causes of HAB’s show that warm, still moving water seems to be the most ideal growing conditions for dense algal blooms (NOAA, 2017). A surge of nutrients, such as lawn or agricultural fertilizer runoff, can also cause a large bloom to occur. When it comes to HAB’s, the best course of action is to recognize the signs of contamination and simply avoid contact with the water.

By Gloria Avila

Sites that track HAB’s that may be of use this summer:

Lake Champlain: https://ahs-vt.maps.arcgis.com/apps/webappviewer/index.html?id=a46d42c05e864a198ab5dc152f9d09b9

Chesapeake Bay: http://eyesonthebay.dnr.maryland.gov/eyesonthebay/habs.cfm

Lake Erie: https://tidesandcurrents.noaa.gov/hab/lakeerie.html

Florida: https://floridadep.gov/AlgalBloom

Resources:

Centers for Disease Control and Prevention. (2021, April 19). Protect Yourself and Your Pets. Centers for Disease Control and Prevention. https://www.cdc.gov/habs/prevention-control.html.

ASPCA. (n.d.). Pet Safety Alert: The Rising Dangers of Blue-Green Algae. ASPCA. https://www.aspca.org/news/pet-safety-alert-rising-dangers-blue-green-algae#:~:text=Dogs%20can%20develop%20poisoning%20when,Seizures.

US Department of Commerce, N. O. and A. A. (2014, August 1). Why do harmful algal blooms occur? NOAA’s National Ocean Service. https://oceanservice.noaa.gov/facts/why_habs.html.

Creek Week: Agricultural Grazing & Its Impact on Streams

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Headwaters throughout the United States constantly face many pressures that threaten their integrity. New housing developments, new roads, yards and agricultural systems all introduce different forms of contamination into freshwater systems. One prominent streamside pressure throughout the country is agricultural grazing. Roaming livestock feeds on, or grazes, vegetation in fields and streams. This process can lead to rapid declines in stream health if not properly managed.

In the United States, agriculture is a multi-billion-dollar industry that sees universal demand from consumers. This incredibly high demand directly leads to extensive changes to our watersheds to account for the presence of livestock.

To meet this demand, open space is converted into farmland suitable for species like cows to roam and consume vegetation on land or in water, if lakes or streams are present. This shift to intensive use from meadow or forest systems introduces stresses to the riparian areas and waters that did not exist before. After conversion, our waters may experience increased sediment deposition from nearby land, increased nutrient loads that come from improperly managed pastures, and streambank damage from increased use from livestock. These stresses and pollutants come from non-point sources, making it hard to pinpoint exactly where they originate. Finding a universal solution is even harder, as a system wide approach should be taken to ensure water quality is preserved. Recommendations to minimize damage exist, but sometimes they can fall short.

There are many solutions available for pasture and livestock owners that not only benefit the environment but can also benefit farmers by decreasing the amount of time and money invested. One of the simplest solutions is to ensure that pasture vegetation maintains a minimum height of 4 inches. When the vegetation is kept near this height, root systems are given the opportunity to grow deeper and hold soil and excess nutrients in place.

Rotational grazing is another solution available to farmers that benefits people, water, livestock, and birds alike when enough space is available. Rotational grazing requires pasture managers to divide their land into different sections, or paddocks. When land is divided, livestock is kept to graze in one section while the vegetation in other paddocks grows out. When growth is depleted in one section and lush in another means livestock can be moved based on plant growth ensuring food and ground cover is sufficient for both the animals and the environment. The ungrazed plant growth serves as an important habitat for ground nesting birds like meadowlarks and an important nutrient barrier for our waters.

When improper practices and bare minimum efforts are applied, sediment from cattle walking paths and fields can be washed into the waterways, potentially smothering algae, fish and aquatic insects that call these waters home. Additionally, if streams are small enough, grazing can occur directly in the streambed or on the riparian buffer that is directly protecting the stream. This can cause foliage to die back and expose the streambanks to new conditions where they can cause erosion downstream, impacting other landowners.

Dust is dangerous in the water, but so are fertilizers, pesticides and nutrients from livestock waste that can leach into waters when riparian areas are damaged in heavily grazed systems. Roots from trees and riparian vegetation hold these compounds in the soil column where they are essentially inert. Without sufficient buffers along waterways, widespread death of fish and other stream wildlife is bound to happen when algae growth can inhibit proper levels of vital chemicals like oxygen.

In areas where it is possible, adding fencing around streams to reduce the impact of grazing animals ensures riparian vegetation can grow and root systems can remain intact. Fencing in grazing heavy habitats can also increase activity of pollinators and birds by ensuring specific habitats and conditions needed to host these groups are present.

Grazing comes in many forms. Large swaths of land can be used by cattle ranchers for habitat and feed or smaller plots can be used. Regardless, unless proper measures are taken to ensure sediment loss and nutrient retention are kept at appropriate levels to maintain healthy waters, this non-point pollution source can impact millions of downstream neighbors when managed improperly.

By Zack Smith

Resources:

Agouridis, C. T., Workman, S. R., Warner, R. C., & Jennings, G. D. (2005). Livestock grazing

management impacts on stream water quality: a review 1. JAWRA Journal of the American Water Resources Association, 41(3), 591-606.

Cole, L. J., Brocklehurst, S., Robertson, D., Harrison, W., & McCracken, D. I. (2015). Riparian

buffer strips: Their role in the conservation of insect pollinators in intensive grassland systems. Agriculture, Ecosystems & Environment, 211, 207-220.

DeYoung, J., & Leep, R. (n.d.). Grazing Streamside Pastures.

https://forage.msu.edu/extension/grazing-streamside-pastures/.

Undersander, D., Albert, B., Cosgrove, D., Johnson, D., & Peterson, P. (2002). Pastures for Profit: A Guide to Rotational Grazing. National Resources Conservation Service: USDA. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1097378.pdf.

Creek Week: A Hidden Stream Engineer

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Ecosystem engineers are species that change the habitats in which they live. In the Trust’s program area, one ecosystem engineer that many would first think of is a beaver. However, there is another ecosystem engineer in our waters that is changing the way our streams and rivers flow: the Caddisfly.

While small, these small insects are incredibly important in their systems. Caddisflies are sensitive to pollution and other environmental changes, and by assessing their presence, stream scientists are able to get a good understanding of a stream’s health. If caddisflies are present and disappear, that may indicate stream conditions have changed enough to a point where caddisflies cannot live there anymore. Alternatively, if caddisflies have not historically been in a stream and appear, that could point to positive changes in a stream’s quality.

Perhaps one of the most important steps to using caddisflies to assess stream quality is knowing how to identify them. With many different types of aquatic insects living in our streams, being able to distinguish a caddisfly from another species ensures that we can be fully sure that we understand the communities in our waters.

Caddisflies have life stages in both the water and on land, but for our purposes we’ll be focusing on the aquatic stage of their life when they are larvae. To identify if an insect is a caddisfly, first look at the shape of its body. These macroinvertebrates, or animals without backbones, have long bodies that are usually smaller than 45 millimeters or about the size of a paperclip. Their heads have hard skin compared to the rest of their bodies and no antennae. They have 3 pairs (or 6 total) legs extending from their middle body segment which is called the thorax. Their abdomen, which is the segment farthest from the head, will be soft and fleshy with branched gills. The most notable feature of many caddisflies is a case that they make out of aquatic debris like branches, rocks and dead plants.

A Giant Case Maker Caddisfly is pictured here. Its case is made from stream debris like small twigs. The Caddisfly’s head is outside of its case where you can see its hardened head and legs extending from its thorax.

Caddisflies are in the taxonomic order Trichoptera and are very closely related to butterflies and moths, and use silk to build their unique cases! Found on rocks, logs, and other objects on streambeds, some caddisflies use silk to spin nets to construct their homes.  When found in large numbers, their silk nets have been known to improve the stability of streambeds around the world. In multiple studies looking at caddisfly larvae’s impact on the stability of the stream bed (also called substrate) during floods, it was found that the presence of certain caddisflies can hold substrate in place in many floods. This is very important because as our waters face more intense flooding caused by climate change, habitat stability for aquatic species is put at risk. Net spinning caddisflies decrease the chances of streambed removal by increasing the stress or pressure needed to push the sand, pebbles, gravel and larger rocks downstream. A stable refuge from stormwater is created in the process, and other species like small fish, crayfish, other aquatic insects and vegetation are less likely to wash away when high velocity flood waters come through.

Though small, the abundance of caddisfly larvae in our headwaters is important because of their importance in identifying and maintaining a healthy stream habitat. When spinning nets, these larvae are inadvertently benefitting other organisms in their system and ensuring downstream species are not disturbed by excess inflow of sediments. Despite the caddisfly’s small size, the importance of this ecosystem engineer in our local watersheds is very large! While it may take thousands of caddisflies to make an impact, their presence is felt by many stream residents.

By Zack Smith

Resources:

Cardinale, B. J., Gelmann, E. R., & Palmer, M. A. (2004). Net spinning caddisflies as stream ecosystem engineers: the influence of Hydropsyche on benthic substrate stability. Functional Ecology, 18(3), 381-387.

Johnson, M. F., Reid, I., Rice, S. P., & Wood, P. J. (2009). Stabilization of fine gravels by net‐spinning caddisfly larvae. Earth Surface Processes and Landforms, 34(3), 413-423.

Voshell, J. R. (2003). A Guide to Common Freshwater Invertebrates of North America.    McDonald & Woodward Pub.