Lee B. Hotchkiss and Beverly Stern
In any region of our country, the politically determined state boundaries are useful for governing the social and economic events of everyday life (figure 3). If, however, we want to study the geologic features and processes in a region, we must look beyond the political boundaries and choose a different focus.
Since this unit focuses on water in general and the Mill River in particular, we will begin by looking at maps which show Connecticut’s three major rivers (figure 4), the state’s eight major drainage basins (figure 5) and the Mill River Drainage Basin (figure 6).
Figure 4 shows the Connecticut, Housatonic and Thames Rivers. Some things to notice are as follows: (1) the Connecticut and Housatonic Rivers originate outside of Connecticut. The Housatonic originates in Massachusetts and the Connecticut in Canada. (2) All three rivers flow south and empty into Long Island Sound. (3) The Connecticut River forms the boundaries between Vermont and New Hampshire and then crosses Massachusetts and Connecticut on its way to the Sound.
Figure 5 shows the major drainage basins in Connecticut. A drainage basin is an area separated from adjacent basins by a divide or ridge. All surface water originating in a basin moves to lower levels and eventually leaves the basin at the lowest point in the divide through which the main river flows.
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Some things to notice are as follows: (1) There are eight major drainage basins in Connecticut. Six of the drainage basins are shared with other states. Only two drainage basins fall completely within state lines. (2) Drainage basin #4 is the Connecticut Valley which drains parts of Canada, Vermont, New Hampshire, Massachusetts and Connecticut before emptying into Long Island Sound. Anything that would spoil the water at any point would be carried south through Connecticut to the Sound. (3) New Haven is part of drainage basin #5. This major basin has four large sub-basins, 50, 51, 52 and 53. Located in the north and eastern part of sub-basin 53 is the Mill River System Drainage Basin. The Mill River System (figure 4) is made up of two smaller drainage basins, the Willow Brook and Mill River drainage basins. (4) Basins 7, 2 and 51 are actually composites of separate, small basins that do not always connect with each other. They are not properly drainage basins themselves, though they are considered as basins on the maps we use in this unit.
There are two maps that are needed at this point, a
State of Connecticut
relief map
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and the
Natural Drainage Basins in Connecticut
map.
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Using the
State of Connecticut
relief map, follow the Housatonic and Thames rivers as they flow south through mountainous regions and the Connecticut River as it flows south through the lowlands of the Connecticut Valley then leaves the valley just above Middletown and cuts through a water gap into the eastern highlands. Notice this map’s scale and what it shows particularly well.
On the
Natural Drainage Basins in Connecticut
map, locate the eight major drainage basins and the four large sub-basins 50, 51, 52 and 53. Next locate the smaller sub-basins 5301 and 5302 which are the Willow Brook and Mill River drainage basins respectively. Locate the arrow indicating where Willow Brook basin empties into Mill River. Notice its scale and the special information it gives.
These maps can serve as the data basis for several types of math lessons using map scales, making scale and time lines, constructing river profiles and determining basin contours and areas. Three example lessons follow: Lesson Plan 1 works with map scales, Lesson Plan 2 uses both scale and contour lines in constructing a river profile, and Lesson Plan 3 works with knowing the names of seven rivers and sketching the bounds of a water basin. How to make and use scale and time lines is simply and clearly explained in Dickinson’s
Map and Air Photograph
.
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