Where your water goes

Rain that falls on Grand Forks ends up in Hudson Bay

1. Your sub-basin

   Lower Red-Nelson

2. then

   Nelson River

3. It arrives here

   Hudson Bay

An enormous, cold, inland sea is the destination — water from here flows north rather than south, which surprises most people who look at a map for the first time. It is ice-covered for much of the year, so the whole system is on a short, violent, snowmelt-driven schedule.

Basin 090203 (USGS hydrologic unit)

Under your feet

Grand Forks sits on Late Ordovician sedimentary rock

About 458 million years old — from the age of the first forests, amphibians and reptiles.

All the kinds of rock, and how each one forms →

1. At the surface458 million years oldNeither way

   Sedimentary rock

   Paleozoic sedimentary rocks · Late Ordovician

   What it is

   The family that covers about three quarters of the land surface, in a thin skin over everything else. Some geological maps say only this much, which still tells you it will be layered and may hold fossils.

   How it wears

   Along its bedding planes, layer by layer, at a rate set by whatever the layers are made of — which is why sedimentary country weathers into steps.

   What it means above ground

   Layered country with flat-topped hills and stepped valley sides. What grows on it depends entirely on whether the beds are limey or sandy, which is the question worth asking next.

2. Below, layer 2458 million years oldNeither way

   Sedimentary rock

   Late Ordovician sedimentary · Late Ordovician

   What it is