April 24, 2000

here is a gathering in the woods below the UConn forest. Raindrops, snowmelt, and underground springs gather there, to form the water that flows to meet our needs.

The familiar part of the story involves plumbing. The geological part lies hidden beneath the mountain bike trails above the Fenton River north of Gurleyville Road. Beyond the obvious - that water falls as rain, soaks into the soil, and is pumped and piped to meet our needs - what is actually happening underfoot?

Every faucet at UConn is fed by a small pipe linked to larger pipes, water mains, and underground conduits that ultimately head towards "Towers," the aqua-blue water tanks in the northern part of the campus.

This "distributary" system is fed by a "tributary" system of underground drainage that begins as precipitation over the entire landscape and ends in a single pipeline carrying water up from the Fenton River.

Working backwards, the pipeline collects water from a series of wells that gather water seeping quietly towards them from layers of permeable sand, which, in turn, drain billions of tiny "pores" between each and every grain of sand.

The fate of rainfall on a parking lot is self-evident: drops fall, splash apart, recombine, then flow - film-like - towards the nearest drain. Something similar also happens in the forest, especially during early spring, when the soil is saturated.

Drops falling from the sky and dripping leaves trickle downward until they reach a zone where the pore spaces are full. Usually this occurs above bedrock or till, a hard muddy stratum pasted to the land by moving ice. These materials prevent deeper seepage, allowing the water to flow sideways and slightly downhill towards lowland meadows. There, the till and rock are replaced by a massive porous aquifer composed of yellow-gray sand and gravel deposited about 18,000 years ago, when the disappearing glacier released its sediment load and washed it clean.

Groundwater moving into the aquifer from higher slopes piles up faster than it can drain away, raising the water pressure slightly, and forcing the water to move through the sand and gravel towards the Fenton River where, under normal circumstances, it drains to the sea.

Our wells intercept this age-old system, sucking some of the water away before it has a chance to reach the stream. Infiltrated rain and snowmelt, previously used only by forests and streams, now has a third principal user, an academic one. The more water we take, the less there is available for trout and trees.

Robert Thorson