Monitoring Efforts in Lancaster County Watersheds

Another essential nutrient for plant growth is phosphorus. This element is commonly found in agricultural fertilizers, manure, and wastewater plants. An excess of phosphorus, with nitrates, in waterways can increase the rate of eutrophication. Again, this reduces dissolved oxygen as it increases the amount of mineral and organic nutrients (think algal blooms). The largest contributor to phosphorus in streams is through soil erosion - especially soil found on agricultural or cropland.

The criteria for phosphorus set by  Chapter 93 of the PA Code  is to be less than or equal to 0.1 mg/l in flowing water. The map to the right displays the concentrations of phosphorus taken by water quality monitoring volunteers. The map is divided into watersheds.

Reference:  2018. USGS. Phosphorus and Water. 

In short, dissolved oxygen (DO) is the measurement of how much oxygen is dissolved in water that is available to aquatic organisms. This measurement can tell us a lot of about the health of a stream. Moving water, with rapids or ripples, usually contains more DO than stagnant water. In these unmoving waters, bacteria use oxygen in decaying matter which can lead to oxygen deficiencies. In addition, water temperature and DO are inversely related - the lower the water temperature, the higher the amount of oxygen in the water. DO has a seasonally low concentration in the summer months as this is when the amount of decaying organic matter is the highest. A stream with sustained levels of DO at 4.0 or lower, is not habitable by aquatic life.

 Chapter 93 of the PA Code  has set the DO criteria for streams as to be more than or equal to 6.0 mg/l. The map to the right displays the concentration of DO from the latest readings taken by water quality monitoring volunteers. Remember that DO is dependent on water temperature, so individual readings may have been taken at different times of the year. Please see the yearly charts for a more in detailed look at the DO in Lancaster County.

Reference:  2018. USGS. Dissolved Oxygen and Water. 

Total solids can be dissolved (TDS) or suspended (TSS) in stream water. Dissolved solids consist of calcium, chlorides, iron, sulfate, and other ion particles. Suspended solids are silt and clay particles, plankton, algae, etc. The concentration of dissolved solids affect the balance of water in the cells of aquatic organisms. With an improper cell density, the organism may find it difficult to position itself properly in the water column. High concentrations of suspended solids can act as carriers of toxins as they readily stick to particles, especially in areas where pesticide use is high. In addition, total solids affects water clarity. At higher concentrations, the passage of light through water is decreased, limiting the photosynthetic processes of aquatic plants. Water temperatures will then increase and hold more heat which can lead to more adverse effects.

 Chapter 93 of the PA Code  set the stream water TDS concentration at 500 mg/l on a monthly average and at a maximum concentration of 750 mg/l. The map to the right displays the latest TDS concentrations taken by water quality monitoring volunteers averaged by watershed.

Reference:  2012. EPA. Total Solids. 

Benthic macroinvertebrates are great indicators of water quality in freshwater streams and rivers. These organisms live along the bottom of the stream and usually live most of their lives, if not all, in the water. There are difference groups of macroinvertebrates sorted into pollution tolerances. Unlike fish, they cannot escape the effects of pollution, so the presence of different species can help determine the health of a stream or river. The first group of macroinvertebrates are completely intolerant of pollution and include: mayfly and stonefly nymphs, caddisfly larvae, water pennies, and more. They require the cleanest water and a high concentration of dissolved oxygen. The second group are moderately tolerant of pollution and include: dragonfly and damselfly nymphs, crayfish, alderfly and crane fly larvae, etc. The last group are tolerant of pollution and include: leaches, aquatic worms, blackfly and midge larvae, etc. They can survive in poor quality waters and low dissolved oxygen. If you're interested in learning more about macroinvertebrates in streams,  check out this article! 

The map to the right displays a "grade" for the watersheds based on an average macroinvertebrate index score they received on the latest survey. Group 1 organisms have a higher score than Group 2, with Group 3 having the lowest scores. The number of organisms and species are added and  calculated accordingly to produce a final score . Please note that this specific grade does not fully indicate that the whole watershed has poor/good quality of water - it is rather a generalization. If you're interested in a stream nearby, go out and  survey for yourself !

Reference:  2020. Luell. American Fisheries Society. The importance of macroinvertebrates in freshwater streams. 

Best Management Practices (BMPs) are designed and installed to help reduce the negative environmental impacts we may have on the ecosystem. Usually, watershed BMPs include installing riparian buffer (vegetation along the stream designed to uptake nutrients, slow erosion, and provide shade), fencing to keep livestock out of streams, streambank stabilization, mudsills (to provide habitat and some structural support), vanes (to help guide water), stream crossings (for livestock or vehicles), and ripples/riffles. However, all BMPs help limit the degradation of water quality.

The map displays a "BMP grade" by watersheds. The number of watershed plans, stream restoration length (ft), and the area of riparian buffer (acres) were all taken into account. However, these practices only represent a fraction of the practices that can be implemented. Visit the  Lancaster County Conservation District's  website to find out more about what we do.

Riparian buffers are areas of vegetation that line a stream (about 35 feet wide on each side). The buffers help filter pollutants before they reach the stream, provide food/habitat to terrestrial and aquatic wildlife, stabilize the stream bank, and provide shade.

The addition of vegetation not only helps with reducing soil erosion, it aids in providing shade. Shade keeps the water cooler, which increases the amount of dissolved oxygen and slows the growth of harmful algae. Lower water temperatures also reduces the amount of evaporation that occurs.

Tree tubes are durable plastic that help protect young seedling trees from harsh weather conditions and from animals when they are planted. They also act as a greenhouse, conserving moisture, to encourage growth. Tree tubes are designed to last for years - until the tree is big enough to thrive on their own. The tubes are typically designed to not harm the tree as it grows out of the top.

Wooden stakes are pounded into the ground near the tube and tied to the tube for added support. In addition, bird netting is used at the top of the tube to prevent birds from getting trapped inside of the tube.

Adding stream crossings and fencing to reduce the amount of time livestock are in stream waters greatly improves the quality of the stream. When livestock have unlimited access to a stream, they pollute the water with their waste and even dislodge the soils from the streambanks with their hooves. The dislodging of the soils cause the water to look brown and dirty.

Stream crossings offer a designated area for the livestock to cross and reduce the amount of disturbed sediment. The fencing greatly limits the access to the stream further reducing the amount of pollutants in the stream. With the addition of a riparian buffer (planted in this picture), the pollutants from the fields will be filtered before entering the stream.

Total Dissolved Solids plotted from a monitoring unit located in Conowingo Creek. The concentrations can be influenced by storm events and/or construction. The concentrations are within criteria from the EPA. The Conowingo watershed is the one in the red/coral color.

A line plot displaying the pH measurements from 2022 taken from a monitoring unit. pH (the "potential of Hydrogen") is a measurement of how acidic or basic a solution is. With a scale of 0 - 14, 7 is neutral and greater than that is indicated as basic. A pH of less than 7 is deemed to be acidic. A measurement of pH between 6.0 - 9.0 is deemed to be acceptable by Chapter 93 of the PA Code, with 6.5 - 8.2 is optimal for aquatic plant and animal life. The Conowingo watershed is the one in the red/coral color.

A line plot displaying the salinity levels in Muddy Run, a tributary to Mill Creek. The years 2021 (dark blue), 2022 (light blue with triangles), and 2023 (green) are displayed along with the average (black line). The ocean has a salinity level of about 35 ppt, whereas freshwater streams typically have a level of 0.5 ppt or less. Levels of salinity can be influenced by erosion of soils, precipitation, and evaporation.

A line plot displaying the relationship between dissolved oxygen and water temperature from Mill Creek. As you can see, when the water temperature (in blue) is high, the dissolved oxygen concentration (red) is low - their inverse relationship clear.

A line plot displaying the water temperature over time. The years 2020 (dark blue), 2021 (light blue with triangles), 2022 (green), and 2023 (yellow) are shown with an average between the years (black). The temperature is displayed in Celsius.