River Testing

BMI & P
Benthic-Macro Invertebrates and Phosphorus Testing

Topic: The Health of Centennial Brook and Surrounding Brooks

Background Info: The subgroup of the Ecosystem Services Team, BMI & P (Benthic Macro Invertebrates and Phosphorus) decided to focus on the health of the stream by testing samples of brook water for phosphorus levels as well as observing the general life around the site.
Benthic Macro Invertebrates are bottom dwelling creatures with no backbone that can be seen with the naked eye. Benthic Macro Invertebrates found in a water body are used to indicate health of the water, because each creature has a specific sensitivity to pollution. For instance, some BMI’s such as crayfish (order Decapoda), snails (order Gastropoda) and leeches (order Hirudinea) are much more tolerant of pollutants than others who only thrive in clean, untainted water. Some intolerant BMI’s that indicate low water pollution are mayflies (order Ephemeroptera), stoneflies (order Plecoptera) and caddisflies (order Tricoptera).

Research Question: Are the streams in the Centennial Brook watershed healthy and sustainable? Our definition of healthy and sustainable includes a diverse and plentiful BMI population, as well as an appropriate habitat that houses creatures sensitive to pollution.

Methods of Research: A watershed is defined by a ridge of high land dividing two areas that are drained by different river systems. The Centennial Brook Watershed includes the UVM campus, Staples shopping center, the Fletcher Allen Medical Center, Centennial Field, homes along East Ave., Cholchester Ave., and Patchen Rd., and the Sheraton Hotel and Conference Complex. Sites were chosen along the brooks of the watershed and water samples were taken, labeled and quickly put on ice for preservation. The sample sites and their surroundings were surveyed and inventories of Benthic Macro Invertebrates, amphibians, and trees were taken. The samples were then refrigerated for 24-48 hours and then tested for phosphorus levels using a Phosphorus Hatch Kit. A sample from Site A was then taken fresh and tested to exhibit any discrepancies from being refrigerated.

Tools: Water sample bottles

Insect and Amphibian Field Guide

Tree Field Guide

Phosphorus Hatch Kit

GPS - Garmin 12 model

BMI key - by RiverWatch

Field Notebook

Results: Test Set 1- stored samples: (refrigerated 24-48 hours)

Site	PO₄( mg/L)	Description of Site
A*	1.06	A wetland site. Sample is from culvert originating from Fletcher Allen Hospital wastewater retention ponds. Water smells a little like sulfur. Oxidation of rocks in water shown by the rust coloring on the bottom of rocks. Area thronged with cattails. Found: Tons of snails (order Pelecypoda), 2 small dragonfly larva (order Odonata), a damselfly (order Odonata)with possible deformed wings, eggmasses of some type, crayfish (order Decapoda) reminants. Bottom of stream is rubble and fine silt. 25% inbeddedness of the rubble into the riverbed. North side of clearing is all herbaceous with no shade. South side is dominated by hemlock and pine trees.
B	0.00	Barely any vegetation and trees around. Eroded bank of stream. Sandy bottom. No BMI's, only minnows. Dogs frequent the brook.
C	0.04	A bend in Centennial Brook. Rubble and gravel bottom along with silt and algea coverage in the brook bed. 60% inbeddedness. Found: Midgefly larva, 3 adult damsel flies, 3 frogs, 5 minnows, snail masses. Box Elder trees vegitate the banks.
D	0.01	Sandy bottom at a tree crossing of the Wool Pulley Brook. Found: 10 minnows, 2 frogs, damsel fly. Gray Birch and Black Ash trees on banks. 90% canopy coverage. Also found: iron fixing bacteria pond, idendified by its oily appearance on the surface of water.
E	0.33	The mouth of the Winooski River where Centennial Brook ends. Murky, muddy water. Lack of biodiversity (defined by the variability and numbers of living organism found within a specified geographic region) . High grass along banks. Stagnant water. 10% canopy coverage.

* testing error- didn't draw full sample volume into vacutainer vial when testing phosphorus level.
culvert SITE A

Test Set 2

Site	PO₄( mg/L)	Description of Site
A (repeat)	2.75	A wetland site. Sample is from culvert originating from hospital wastewater retention ponds. Water smells a little like sulfur. Oxidation of rocks in water. Area thronged with cattails. Tons of snails. Found: 2 small dragonfly larva, a damselfly with possible deformed wings, eggmasses of some type, crayfish reminants. Bottom of stream is rubble and fine silt. 25% inbeddedness. North side of clearing is all herbatious with no shade. South side is dominated by hemlock and pine trees.
A (fresh sample)	2.35	A wetland site. Sample is from culvert originating from hospital wastewater retention ponds. Water smells a little like sulfur. Oxidation of rocks in water. Area thronged with cattails. Tons of snails. Found: 2 small dragonfly larva, a damselfly with possible deformed wings, eggmasses of some type, crayfish reminants. Bottom of stream is rubble and fine silt. 25% inbeddedness. North side of clearing is all herbatious with no shade. South side is dominated by hemlock and pine trees.
F (fresh sample)	2.20	Sample taken from the upper hospital wastewater retention pond. No canopy coverage. Duckweed and high grasses along banks. Lack of biodiversity. Sandy bottom, no rocks, gravel or rubble at bottom.

Conclusion:After testing phosphorous levels in each sample taken from the test, the levels of phosphorus clearly indicated that the levels of phosphorus in areas around the Fletcher Allen wastewater retention ponds were heavily polluted, giving off levels of PO₄ up to 2.75 mg/L. Any level of phosphorus is unwanted, however any levels above 1 are considered critical. Team BMI & P's results supported the fact that the Centennial Brook watershed is one of the nine impaired watersheds in Chittenden County.