San Lorenzo Creek -- Bayland Habitat Enhancement


Objective: The development of a conceptual design of the wetland at the mouth of San Lorenzo 
Creek that will improve existing habitat for the benefit of native wildlife and encourages linkages to 
adjacent habitats.

Task 1 -- Project Goals

Project goals will be developed through various brainstorm sessions with interested stakeholders.  A 
set of ecological and hydrological goals and objectives will then be established. Examples of project 
goals include:

  Increasing habitat connectivity (tidal channel to bay plane to uplands) 
  Maintaining or enhancing flood capacity 
  Enhancing tidal flux 
  Creating wildlife refugia 
  Educational signage

Task 2 -- Seek Stakeholder Input

The conceptual design process will be reviewed by key stakeholders within the Alameda County Public 
Works Agency, the city of San Leandro, Oro Loma Sanitary District, state Department of Fish and Game, 
U.S. Fish and Wildlife Service, Coastal Conservancy, and other pertinent regulatory agencies.

Task 3 -- Citizen Advisory Committee

The formation of a citizen advisory committee (CAV) will ensure that the public's vision of a restored 
bayland is well represented.  This committee will be instrumental in forming a final conceptual design 
of the site and will comment during all stages of this restoration process.  The CAV will include the 
Friends of San Lorenzo Creek.

Task 4 -- Biological Reconnaissance Survey

Searches of data bases on special status species for the project area.

Field surveys to document existing conditions at the site, including habitat types, existing 
vegetation, existing value of the site for special status species (salt marsh harvest mouse, clapper 
rail, etc.). 

In addition to describing findings, maps of vegetation and/or habitat types at the project site 
will be produced, as well as maps of special status species locations (if applicable). 

Task 5 -- Wetlands Delineation Survey (Elisa Gill and Inta)

Conduct a field survey of wetlands on the site, using the standard three-parameter approach required by 
the Army Corps. 

Map the wetlands and write a report detailing our findings. 

Task 6 -- Conceptual Design

Based on the project goals identified in Task 1, a list of design alternatives and associated costs 
will be developed.  Each alternative will provide a different method for restoring the wetland and 
adjacent transitional ecotone and upland habitat.  A preferred alternative will be selected with the 
assistance  of the citizens advisory committee, stakeholders, and consultants.  A conceptual design 
will be developed for this preferred alternative and will encompass adjacent habitats.  This will be 
the design that most effectively creates an environment beneficial to wildlife and their habitat.  
A biologically based alternative for restoration of the marsh will be developed based on field work and 
review of other data.

The biological implications of other alternatives developed will be evaluated. 

A complete analysis of each proposed alternative design for restoring tidal flow to the restoration 
site will be evaluated.  The analysis may include any or all of the following steps:

(a) Data Review, including:

  Culvert dimensions including length, invert elevations and cross-sectional area (diamter);

  Topographic information for the study area, adjacent San Lorenzo Creek and bay front.

  Tide data for San Lorenzo Creek and the Bay.

  Information gathered from the biological reconnaissance and wetlands delineation 

(b)Hydrologic Modeling

Hydrologic modeling will be performed to evaluate the wetland restoration alternatives.

The model setup would change for each alternative and may include the following variations: with or 
without internal channels, culvert sizes and numbers, type of culverts, and/or a slide/flap tide gate 
that will provide tidal hydrology capable of sustaining emergent vegetation while providing flood 
protection for adjacent activities and uses.  

Task 7 -- Design Report

ESA will write the biological site conditions sections of the conceptual plan.

ESA will contribute to making recommendations for marsh restoration, based primarily on biological and 
ecological factors. 

ESA will compile its contributions as well as sections written by others (i.e., hydrologic modeling, 
stakeholders suggestions) into a conceptual plan for restoration of the marsh. 

Task 8 -- After-Analysis Report for Permitting Purposes (dependent upon funding availability)

The potential to obtain mitigation credit for the enhancement work or to have the site serve as a 
mitigation bank will be investigated with the U.S. Army Corps of Engineers and the San Francisco bay 
Conservation and Development Commission staff.  Factors to be evaluated include total area and baseline 
functions and values relative to the anticipated enhancement of wetland functions and values.

Funding: $94,204 (Source: Coastal Impact Assessment Program) Dates: March - November 2006 Contractor: Emmanuel da Costa Alameda County Flood Control & Water Conservation District 951 Turner Court, Room 300 Hayward, CA 94545 Tel: 510.670.6479 Fax: 510.670.5262