A Living Library

Roots of the Problem:
Environmentalist Says Trees Could Reduce Flooding

By Ethan Fletcher | Staff Writer
Published on Tuesday, May 25, 2004
Page 6

There have been many suggestions for how to solve the flooding in the Excelsior District since a torrential rainstorm in February filled hundreds of homes with sewage.

From a complete overhaul of San Francisco's outdated sewer system to better emergency response times from the Public Utilities and Public Works departments, talk has focused on what The City can do to prevent future flooding. But Bonnie Sherk, a San Francisco landscape architect and artist, says people are looking at excess water in the wrong way.

The sewage overflows in many houses in the Mission Terrace and Excelsior neighborhoods happened because those neighborhoods lie in the flood plain of the Cayuga Valley. In addition to the water draining from higher areas, the nearly forgotten Islais Creek flows directly underneath the neighborhoods, causing what Sherk said was a high water table.

"Water is a valuable resource and people are looking at it negatively, but we're lucky that we do have so much of it," she said.

According to Sherk, the problem is that with so much of the area paved over in recent years, this valuable resource has no place to go except into streets or homes -- as evidenced by the torrents of water flowing down Cayuga Avenue during February's floods.

A simple and infinitely prettier solution, Sherk says, is to take advantage of the underground water by planting more trees and green areas that would naturally suck up the excess water.

Adding fuel to her argument is the fact that one of the only streets in the Excelsior flowing down from McLaren Park that did not experience flooding was Persia Avenue -- a tree-lined street.

Reduced flooding would actually be a side benefit to Sherk's master plan for the area. Five years ago, she started the Living Library and Think Park, which has since turned into a beautiful oasis of green amid the concrete jungle that is Balboa High School, James Denman Middle School and San Miguel Child Development Center complex in the Excelsior. The Living Library was created with the help of local students and consists of trees, flower and vegetable gardens, and creative art installations, including a student-created mosaic mural along the outside school walls depicting the past history of the area around the schools.

Sherk envisions the entire school complex existing as a community park with native species of plants and ponds all fed by the Islais Creek now flowing unused below. Islais Creek also connects to the Living Library at the Junipero Serra Child Development Center in Bernal Heights, which Sherk hopes could someday be linked to nearby parks with a tree-lined nature path.