Lake Gregory Sediment Management and Bioretention Project

Status Permitting County San Bernardino
Project Type Compensatory mitigation Location 34.24237° N, -117.27704° W Map
Project Area (Acres) 1.19 Last Updated 13 April 2022
Project Abstract Purpose of the Project is to construct a debris basin to capture and desilt storm flows prior to discharging to Lake Gregory (West Basin), dredge two areas of the lake to increase depth of water and restore lacustrine habitat (South Beach and South Channel), and stabilize a portion of Houston Creek South to enhance the quality of stormwater flows.
Administrative Region Lahontan Regional Water Quality Control Board - Tiffany Steinert, Jan Zimmerman, Elizabeth van Diepen, LRWQCB

Project Identification

6B361601001 SWRCB - 401 Certification Letter (e.g., Site Number or WDID)
SPL-2016-00031-SLP USACE - Nationwide General Permit

Habitat Plan

Site NamePhaseActivitySubActivitiesHabitatSubHabitatAcresActivity StatusWater Regime
Remove - South Beach None Restoration (unspecified) Sediment Management Lacustrine Wetland Open water No Data Proposed Unknown/Unspecified
Remove - West Basin None Unknown/Unspecified Unspecified Seasonal Wetland Unknown/Unspecified 0.29 Proposed Riparian
Willow Island None Creation/Establishment Sediment Management Lacustrine Wetland Open water 0.58 Permitting
Willow Island None Creation/Establishment Sediment Management Riverine Wetland Channel 0.10 Permitting
Willow Island None Enhancement Sediment Management Riverine Wetland Riparian area 0.22 Permitting

Related Habitat Impacts

HabitatAcres LostType of Loss
Buffer area < 0.1 Lost Temporary
Depressional Wetland 0.23 Lost Permanent
Lacustrine Wetland 4.21 Lost Temporary
Riverine Wetland 0.23 Lost Permanent
Riverine Wetland 0.89 Lost Temporary


Remove - South Beach Unknown/Unspecified No Data
Willow Island Permitting 0.90


DateTypeDescriptionSite Name
2016-11-04 Project start date Estimated date


Agency Staff Maureen Snelgrove San Bernardino County Regional Parks
Contact Tim Millington San Bernardino County Special District
Contact David Gettel San Bernardino County Griffin Holdings


None Creation/Establishment San Bernardino County
None Enhancement San Bernardino County

Related CRAM Assessments

Visit DateVersionSite NameWetland TypeIndex Score
No Data

No files found.

How to Use the Habitat Development Curve

Habitat Development Curves (HDCs) are used to determine the developmental status and trajectory of on-the-ground projects to create, restore, or enhance California wetland and stream habitats. Each HDC is based on assessments of habitat condition for different age areas of one habitat type that in aggregate represent the full spectrum of habitat development. The assessments of condition are provided by expert applications of the California Rapid Assessment Method (CRAM). Visit the CRAM website for more information about CRAM.

For each HDC, reference condition is represented by areas of a habitat that consistently get very high CRAM scores, have not been subject to disruptive management practices, and exist within landscapes that are protected and managed for their natural conditions. The horizontal lines intersecting the top of an HDC represent the mean CRAM score and standard deviation of scores for 25 qualifying reference areas.

The age of a project is estimated as the elapsed time in years between the groundwork end date for the project and the date of the CRAM assessment. To add or update a groundwork end date, use the Project Events form in Project Tracker ( The minimum age in years of a non-project area, including any natural reference area, is estimated from all available local information, including historical maps and imagery, historical written accounts, and place-specific scientific studies of habitat development.

An HDC can be used to address the following questions:

  1. At what time in the future will the area of assessed habitat achieve the reference condition or other milestones in habitat development? The HDC can answer this question if the CRAM score for the assessed area is within the confidence interval of the HDC. The answer is the time in years along the HDC between the current age of the assessed area and the future date corresponding to the intersection of the HDC and the reference condition or other milestone.
  2. Is the area of assessed habitat likely to develop faster, slower, or at the same pace as most other areas of the same habitat type? The habitat area is likely to develop faster, slower, or at the same pace if the CRAM score for the area is above, below, or within the confidence interval of the HDC, respectively.
  3. What can be done to improve the condition of the habitat area or to increase its rate of development? HDCs by themselves cannot answer this question. Possible answers can be inferred by the following analysis that involves HDCs:
    1. Examine the HDC for each of the four CRAM Attributes;
    2. Identify the Attribute(s) scoring below the HDC;
    3. For any low-scoring Attribute, examine the component Metric Scores (note: the Metric Scores for any public CRAM assessment in the CRAM database can be obtained through EcoAtlas);
    4. Assume the low score of an Attribute is due to its low-scoring Metric(s);
    5. Consider modifying the design or management of the habitat area in ways that will sustainably increase its score(s) for the low-scoring Metric(s).

For more information about CRAM Attributes and Metrics, including their scientific rationale, see the CRAM Manual.

Display Habitat Development Curves For Wetland Type:

CRAM Site Scores