Mitigation for Caltrans State Route 138 Widening Project - Region 6

Status Proposed County San Bernardino
Project Type Compensatory mitigation Location 34.40625° N, -117.62815° W Map
Project Area (Acres) 1.21 Last Updated 26 August 2016

Project Identification

SB140001IN SWRCB - 401 Certification Letter (e.g., Site Number or WDID)
SB13004IN SWRCB - 401 Certification Letter (e.g., Site Number or WDID)

Habitat Plan

ActivityHabitatSubHabitatAcresActivity StatusWater Regime
Acquisition/Preservation/Protection Riverine Wetland Channel 1.21 Planning/Scoping

Related Habitat Impacts

HabitatAcres LostType of Loss
No Data


Western Mitigation Area Parcels for the State Route 138 Widening Project Proposed 1.21


DateTypeDescriptionSite Name
2016-08-01 Project submitted Compensatory mitigation plan submitted


Contact Brian Dailey State Water Resources Control Board Not applicable/Unknown
Contact Jan Zimmerman Lahontan Regional Water Quality Control Board Not applicable/Unknown


Acquisition/Preservation/Protection CDT California Department of Transportation

Related CRAM Assessments

Visit DateVersionSite NameWetland TypeIndex Score
No Data

Performance Criteria

StatusDetailsEvaluation Date
No Data

Project Description

The California Department of Transportation (Caltrans) is widening State Route (SR) 138. The project spans two Regional Water Quality Control Board districts. Off-site mitigation is required as a condition of the 401 Water Quality Certification and Waste Discharge Requirements permits. The study area for the proposed mitigation sites consist of four parcels in two separate locations, separated by approximately ½ mile. The Eastern Mitigation Area consists of Assessor Parcel Numbers (APNs) 3036-121-04 and 3036-121-06 and encompasses 16.3 acres. It occurs at the south end of Silver Rock Road approximately 1.5 miles south of its intersection with SR 138. The Western Mitigation Area consists of APNs 3036-081-04 and 3036-081-05. It occurs at the south end of Pine Tree Road approximately ¾ mile south of the intersection with Green Road. The mitigation sites are found in the unincorporated community of Pinon Hills, San Bernardino County, California. The study area boundary was provided to Amec Foster Wheeler Environment and Infrastructure, Inc. (Amec Foster Wheeler) by Caltrans. Specifically, the study areas are located within Sections 28 and 29 of Township 4 North, Range 7 West as shown on the Phelan and Mescal Creek, California, United States Geological Survey (USGS) 7.5 minute topographic quadrangles. The geographic coordinates near the middle of the Eastern Mitigation Area are 34.40269° North latitude and 117.61831° West longitude and the geographic coordinates near the middle of the Western Mitigation Area are 34.40622° North latitude and 117.62817° West longitude.
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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.

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CRAM Site Scores