THE STREAMER NEWSLETTER

Streamer: Summer 2000

The Upper Charles River from Dover to Hopkinton is frequently not in compliance with state and federal water quality standards. Additionally, the river is under increasing stress during dry summer months as the normally low seasonal flows are reduced further by the impacts of development. CRWA's activities in the Upper Charles cover three related projects (Watershed Permitting, Ground Water Management Alternatives, and Watershed Modeling) that together have the potential to reduce nutrient loads to the river and also increase flow, both resulting in decreased nutrient concentrations in the river.

Most water quality problems in the Upper Charles are related to phosphorus which promotes algal and vegetative growth. Impoundments behind dams are particularly susceptible to phosphorus because decay of vegetative material yields organic sediments that cloud the water and slowly fill the impoundment. High phosphorus concentrations in the river are caused by discharges from nonpoint (eg. lawns, golf courses) and point sources (eg. wastewater treatment plants), or low flows. The US Environmental Protection Agency's suggested instream limit of 0.05 milligrams per liter for phosphorus is often exceeded in the Upper Charles, typically in summer when most stream flow is discharge from wastewater treatment plants.

The Watershed Permitting project will determine the impacts of permitted water resource uses on the river and should help streamline the permitting process to reduce nutrient concentrations and increase river flow. In many cases, permits affecting groundwater withdrawals, wastewater discharges, and stormwater are dealt with as separate entities, on different renewal cycles, and are not coordinated among towns even though they all ultimately impact the river. By brokering discussion on regional impacts of permits among agencies and communities, CRWA hopes to create a more effective permitting process that will ultimately reduce nutrient concentrations and increase flow in the river.

The Ground Water Management Alternatives project focuses mainly on water quantity and is being conducted by US Geological Survey with CRWA data input. This project aims to produce a computer model of the Upper Charles ground water. The model will then be used to evaluate spatial effects of wells in close proximity, seasonal interactions of ground water and the river, and the effect of future development on both ground water levels and low river flows.

The Watershed Modeling project will develop a watershed-scale river model to evaluate the effects of nutrients, sediments, and fecal coliform. This work is coordinated closely with the Ground Water project so that the ground water recharge component from the watershed model can be used as the input to the ground water model. This close coupling of work will ensure that the two modeling efforts use consistent weather data, pumping records, and land use for both studies.

Both models ultimately will be linked so that the effects of both the water quantity and quality can be simultaneously evaluated. CRWA's goal is to use such a tool to evaluate the effects of environmentally-based land use planning on water quantity and quality.