The Drainage Divides of Montclair Creek

 

Last month I invoked the names of Thomas Jefferson and Major John Wesley Powell in trying to answer two questions: 1) How did we get in the position of streams needing restoration? 2) Who got us there?

Congress rejected Powell’s proposal that drainage divides should be the organizing land use principle in the west. Instead they chose Cartesian (or Jeffersonian) boundaries drawn along arbitrary lines (rectilinear surveys).  What would implementing Powell’s proposal have looked like?  What would the superimposition of that proposal on the current land use pattern look like?

First, what is a drainage divide? I’ll ignore Albert Einstein’s thoughts regarding Sir Isaac Newton’s theory of gravitation. Let’s accept that water flows downhill, starting from the highest elevation at which it hits the ground, either as rain or as snow. A watershed is a geographic area where all water flowing downhill departs through a common, shared exit point, the lowest location in the watershed. Watersheds are defined by connecting every high point to the next, linking all of the highest ridges that send water down to the shared low point. The connected “highest ridges” are the drainage divides.

The Eisenhower Tunnel crosses under the Continental Divide between the Atlantic and Pacific watersheds. Loveland Pass and Berthoud Pass cross that same divide. Monument Hill (on I-25 south of Denver towards Colorado Springs) crosses the South Platte River – Arkansas River divide. No matter how big or small they may be, watersheds are all defined by drainage divides. The map above shows some drainage divides in east Denver, (extending approximately from Washington Street east to Havana Street, and from Hampden Avenue north almost to I-70). In particular, note the four watersheds numbered 1 through 4:

1. Montclair Creek

2. Westerly Creek

3. Goldsmith Gulch

4. Harvard Gulch

In watersheds 2 through 4, local activist groups are working with local governments and other entities to pursue stream restoration.

Some of the high points defining the southwest boundary of the Montclair Creek watershed are: Fairmount Cemetery, Monaco Street in front of George Washington High School, the sundial at Cranmer Park, the top of the Botanic Gardens, and the west side of East High School. On the northeast boundary think of: Martin Luther King, Jr. Boulevard just east of Colorado Boulevard, Montview Boulevard at Forest Parkway, Colfax Avenue just of Monaco, 6th Avenue Parkway two blocks east of Quebec, Bayaud at Quebec, and Fairmount Cemetery.

In John Wesley Powell’s world, drainage divide lines would be more pertinent than rectilinear street alignments. They would, in fact, significantly dictate alternative alignments for many streets. Instead, right now, many important streets and intersections are located within the 100-year floodplain of Montclair Creek and its two major branches. In Powell’s world, drainage divides would guide the location of commercial establishments, schools, and hospitals. There are at present numerous shops, schools and hospitals in the 100-year floodplain of Montclair Creek, as mapped by engineering consultants retained by Denver city government a few years ago.

Next month: How might drainage divides have guided the location of parks and open space before buildout of the Montclair Creek watershed? What could be changed in the future?

Brian Hyde is an expert in floodplain management and stream restoration. He wants your feedback at westerly_connect_brian@comcast.net or 720-939-6039.