manzanita village: a case studyturning lemons into lemonade

jennifer j. bitting, pecentral coast water board

outline

• what is manzanita village?• project setting• project history• water quality results• beneficial outcomes • sustainabliliy review• lessons learned

manzanita village: ucsb housing complex

• 6 acre site• eleven 3-story

buildings• six 4-story

buildings• houses 800

students• opened

september 2002

project setting

• mediterranean climate• marine terrace deposits

on sisquoc shale• clay subsoil• degraded grassland and

vernal pool landscape• bordered by the pacific

ocean and campus lagoon

original design

• traditional underground storm sewer system

• buildings too close to vernal pools

no treatment - discharge of phosphorus and nitrate polluted water to the beach, surfer-filled waters?

no volume reduction

increase rate of bluff erosion

habitat for endangered species

designed to meet federal wetland guidelines but not state requirements

plans needed to be modified – ecology professors and research students used the opportunity to recommend bioswales and wetlands to aid in site drainage

new design

75% of the project area flows through biofiltration systems

1300 linear feel of swales

• 4 swale systems with 43 bioswale basins

• 8 experimental plant palettes

2 stormwater wetlands

1 vernal marsh

3 vernal pools

new designbioswales

• 8 experimental plant palettes using:

• 3 rushes:

• juncus mexicanus

• juncus patens

• juncus phaeocephalus

• 3 sedges:

• carex praegracilis

• eleocharis macrostachya

• scirpus maritimus

• single species basins

• rush basins

• sedge basins

• rush and sedge basins

• control basins

bioswale planting september 2002 bioswale vegetated

august 2003

results

water quality results

• 99.5% reduction in nitrates

• 81.8% reduction in phosphates

beneficial outcomes

• potable water vs. reclaimed water

• bioswale clippings make nutrient rich mulch for university landscaping

bioswales watered with reclaimed water grew faster during the plant establishment phase and consequently were able to treat storm water more effectively.

using reclaimed water reduced the use of potable water and reduced the water bill.

sustainability review

• environment– provides habitat for endangered species– reduces pollutants discharged to campus lagoon– does not contribute to bluff erosion

• economics– reduces $ spent on mulch– reduces potable water bill (used reclaimed water for plant

establishment)– takes the place of ordinary landscaping (not irrigated)– does not contribute to loss of real estate (bluff erosion)– less $ spent on underground storm sewer installation and maintenance

• social– boardwalks, viewing terraces and bike trails control traffic and restrict

access to the fragile habitat– entirely wheelchair accessible– educational signs inform students about animal and habitat sensitivity– public health benefit: water is treated before discharge to the beach

and ocean

lessons learned

• design low impact development into the project in the first place!– design cost savings not realized; project

had to be designed twice.

• utilize design change opportunities to make projects more sustainable!

• take advantage of mistakes– potable vs. reclaimed water

sources & more info

• more info:– ucsb cheadle center for biodiversity and

ecological restoration (805) 893-2401 http://ccber.lifesci.ucsb.edu/

• sources:– http://dailynexus.com– http://sustainability.ucsb.edu– http://www.coastalconference.org