Update: Chris Jones updated some details about the population and fecal waste issues. Please follow this link for his post 50 Shades of Brown.
My state of Iowa has a human population of 3.16 million (2018). Demographics are here. Des Moines is the most populous city with over 210,000 residents, then Cedar Rapids (130,405) and Davenport (102,582). The rest of the state is mostly small towns and rural. The many river and stream watersheds are outlined in the following image with the human population noted.
Why do I say the state has a huge population problem? It is because of the large numbers of animals grown in these watersheds. There are about 20-24 million hogs, 250,000 dairy cattle, 1.8 million beef cattle, 80 million laying chickens, and 4.7 million turkeys. Not included are the sheep, goats, horses, deer or Canada geese. These animals create a heavy burden on the water quality of the rivers and streams in the many watersheds around the state. All of which feed into the Missouri and Mississippi Rivers bounding our west and east coastlines.
The University of Iowa Institute of Hydraulic Research in Hydroscience & Engineering (IIHR) helps understand the demands on the water flow throughout the state. It helps engineer solutions to the problems encountered in keeping our waters safe. Water quality engineer Chris Jones recently examined the nitrogen (N), phosphorus (P), and total solid matter (TS) of the animal wastes and compared them to equivalent human N, P, and TS levels. His results were published in his blog and were astounding. Please read his post for the details.
The impact of all those animals raised in Iowa was equivalent to a human population of 134 million people. That ranks our state as the 10th most populous ‘nation’ compared to humans alone, behind Russia and ahead of Mexico. To make his point, he put various equivalent human population centers of the world within the watershed boundaries. It is no wonder our rivers and streams are suffering from critical levels of runoff.
Chris Jones was not trying to pass judgement upon the livestock industry. It is a mainstay in our economy. He says it is important for leaders in the state to examine environmental outcomes along with the economic and regulatory considerations of the industry. I agree.