Exploring Water Flow and Sediment Deposition at Paradise

24 Aug

Hi! My name is Lizzie Sturtevant (’18), one of several students and faculty working on the Mill River Monitoring Project. I am majoring in geoscience and have an interest in hydrology and resource management. I have been working with geoscience professor Robert (Bob) Newton along with Marcia Rojas (18’), Maya Domeshek (18’), and Lynn Watts (17’) to examine water flow and sediment deposition in Paradise Pond and the Mill River during different weather events.

LizzieInField

With support from the Center for the Environment(CEEDS), the Mill River Monitoring Project has brought together students, faculty, and staff with a variety of backgrounds and interests in the search for an alternative method of sediment removal in Paradise Pond that will preserve the health of the river and save the school money while making use of the natural hydraulic power of the Mill River.

As suggested by its name, Paradise Pond is a landmark cherished by members of the Smith community and town of Northampton for its scenic relief and space for boating activities. A resource so central to the scenery on campus does not come without the cost of proper maintenance. Every 8-10 years, Smith College pays to have Paradise Pond dredged to remove accumulated sediment. This expensive process involves the excavation and transportation of the sediment to a landfill.
scenic_paradise

When looking across the mounds of mud and dead leaves that have filled several sections of Paradise Pond, you may have wondered what causes this accumulation of sediment. Naturally, rivers have a balance of sediment inflow and outflow; however, the construction of a dam such as the one used to create Paradise Pond can disrupt this balance by lowering water velocities, thus enabling the deposition and accumulation of sediment (Batuca et. al, 2000).

Sediment In Pond at 1.49.03 PM
A birds-eye view of the sediment in Paradise Pond.

It may be possible to use the natural power of the Mill River to remove this sediment by operating the sluice gate that is located at the base of the campus dam. This project is exploring the possibility of opening the gate during events of high flow to hydraulically erode the sediment and carry it through the gate, ultimately flushing it downstream and into the natural flow of river sediment.

Prior to releasing significant amounts of sediment through the sluice gate, it is important that we know the potential effects of depositing this sediment downstream. To evaluate these risks of contamination, we have taken sediment cores from Paradise Pond and sites downstream to compare their composition. We have been analyzing these cores for contaminants such as mercury, lead, and phosphorous, which could affect the ecosystems downstream if found at higher concentrations in the pond.

RiverRayThe “River Ray” which we use to measure water velocity and discharge.

Laboratory instructor Marney Pratt (biological sciences) has been working with Molly Peek (18′) to measure the invertebrate diversity of the river in order to study the effect of sediment release on the biological communities downstream of the pond. If you have been following the [CEEDS] blog at all, you have already heard from Molly about some of the macroinvertebrates they have found!

Professor Newton, Maya, Marcia, Lyn and I have established four reference sites downstream of Paradise Pond to observe and record sediment deposition following the opening of the sluice gate. Now that we have established our baseline data and characterized the sediment in the pond, we are prepared to test opening the sluice gate to see how the sediment will be deposited downstream. We will keep you updated on our findings as we move forward with our research! 

-Lizzie Sturtevant (’18) lives in Morrow House and plays on Smith’s lacrosse team. She grew up in the Pioneer Valley and now lives in Leyden Massachusetts- only a 35 minute drive from campus. Lizzie fell in love with geology when she studied abroad in New Zealand during her junior year of high school.

Reference Cited:

Batuca, Dan G., and Jan M. Jordaan. Silting and Desilting of Reservoirs. Rotterdam, Netherlands: A.A. Balkema, 2000. Print.

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