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San Diego Canyonlands tackles runoff issue

Posted: January 15th, 2016 | Bankers Hill, Communities, Feature, Top Story | No Comments

by Tershia d’Elgin 

Like most places with hills, Bankers Hill has a valley — Maple Canyon. The canyon’s long, sinuous path from the top of Third Avenue down to West Maple Street is both a connection with nature and a workhorse. The canyon is a haven for birds, animals and hikers.

However, during rainstorms the canyon funnels a rage of stormwater to the San Diego Bay. Erosion, habitat destruction and water pollution are the result, costing taxpayers dearly every year.

Reversing this trend is part of San Diego Canyonlands’ mission in Uptown right now. An umbrella organization for San Diego’s many canyon “friends” groups, Canyonlands builds stewardship for the region’s undeveloped coastal canyons.

As runoff from rainstorms is causing more erosion, the chasm in Maple Canyon in Bankers Hill is more than 12 feet deep in places (Photo by Diego Lynch)

As runoff from rainstorms is causing more erosion, the chasm in Maple Canyon in Bankers Hill is more than 12 feet deep in places, as Tershia d’Elgin shows in both photos. (Photo by Diego Lynch)

“Nearly every rainstorm winds up closing beaches,” said Eric Bowlby, executive director of San Diego Canyonlands. “Harmful bacteria and other pollutants washed from our urban landscape make the ocean a risky environment, for up to 72 hours at a time.”

Many factors contribute to water pollution and other negative impacts, most of them not in the canyons but along the rims and mesas above the canyons. Rooftops, sidewalks, streets and parking lots are impervious. As the land is urbanized, less and less rainfall soaks into the ground. Even turfgrass is a problem. Short-rooted lawns don’t absorb as much water as shrubs and trees. Water slides right off them and is funneled from yards, parking lots and streets through storm drains directly into the canyons.

The runoff is filled with contaminants such as pesticides, fertilizers, tire dust and grease . . . the list goes on and on. Together with rain, this urban swill is funneled through the canyons in ever-greater volume and velocity. Now, instead of meandering streams that wind through deep-rooted native vegetation in the canyon floodplain, filtering and cleaning the water, we have severe erosion causing deeply incised, narrow creek channels where the water rushes through the canyon like a toxic spike on its way to our coastal waters.

This is one reason why the California Coastal Conservancy is investing $300,000 via a grant to San Diego Canyonlands to plan rehabilitation of 12 urban canyons, including Maple Canyon. The agency seeks to restore the natural habitat and functions of the canyons as well as plan sustainable, non-eroding trails so people can safely access and enjoy these precious islands of open space.

(Photo by Diego Lynch)

(Photo by Diego Lynch)

“There are solutions to help individuals play a significant role in capturing and slowing the runoff,” Bowlby said. “Contouring the yard to direct runoff into a garden or to the base of a tree is one easy example.”

Deep-rooted, drought tolerant, plants direct water down into the soil, where the plant and micro-organisms can use and break down the contaminants. As a bonus, trees and shrubs also sequester carbon, clean air, save energy expenditures, and raise property values.

Permeable landscape is but part of capturing rainwater. Roofline gutters and rain barrels are an additional tool. These methods will ease the burden on Maple Canyon, lower water expenditures and improve neighborhood ecosystems. Better landscaping addresses not only downstream impacts, but also the healthy function of microclimates, i.e. individual properties on the rims.

San Diego Canyonlands has organized a survey of Bankers Hill properties and residents. Interns will be canvassing the neighborhood to assess opportunities to increase water retention and water-absorbing landscapes. Residents’ interest in this program will help the organization raise money to help convert landscapes, build sustainability for water resources, and restore Maple Canyon’s natural functions. Look for San Diego Canyonlands volunteers with whom you can discuss possible landscape improvements.

“In the last year we have grown the Friends of Maple Canyon to over 120 Bankers Hill residents,” Bowlby said. “Their enthusiasm is strong and I believe the Bankers Hill community will roll up their sleeves to help solve this challenge.”

Participating is a great way to positively improve your property, your neighborhood and the coast. For more information, contact Eric Bowlby at 619-284-9399 or eric@sdcanyonlands.org.

Tershia d’Elgin, a climate activist, saves and restores wetlands. The University Press of Colorado will publish her book, “The Man Who Thought He Owned Water,” in spring 2016.

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