The river that the mills used for power was the Merrimac River. There were water blocks to control the water flow; too hard or too slow would affect the speed of the wheels and therefore the accuracy of the looms. This was better known as the gate house. The river would also be strained once a week or so when the mills were not is use, in an attempt to clean some of the sewage out. People dumped most of their trash and pollution in the river, making it black and smell bad. In fact, most of the city was quite messy. The flowers and nice brick walkways that are along the river in Lowell now are recent additions, and none of that sort of thing was to be seen in the Lowell before.
Most of the buildings are made of brick or wood. The tall and large