July 31, 2002

 

Mr. Pat Higgins

KRIS Project Field Coordinator

Institute for Fisheries Resources

7981 Eighth Street, Suite N

Arcata California 95521

 

Dear Mr. Higgins,

 

The California Geological Survey (CGS) has completed its review of the Klamath River Information System (KRIS) Gualala website.  CGS previously reviewed and provided comments on the KRIS Gualala CD in a letter dated March 15, 2002. 

 

A major concern with the KRIS Gualala website is the divergence between the KRIS web site and the North Coast Watershed Assessment Program (NCWAP) Gualala River Assessment Report, dated July 19, 2002 (Report).   In particular, the hypotheses and conclusions proposed in the KRIS Gualala website are different from those presented in the NCWAP Report.  In some cases, the conclusions in the KRIS Gualala contradict the conclusions in the NCWAP report.  This is the case regarding the sediment source information.  The NCWAP team has determined that natural sediment sources are the largest contributor in the Gualala River watershed.  However, the KRIS website maintains that anthropogenic factors are the largest contributor of sediment in the basin. 

 

This discrepancy has large implications for future land management decisions and it will be difficult for the Gualala Watershed stakeholders to formulate land use policy and practice if this ambiguity is not resolved.   The KRIS Gualala was developed under contract with the California Department of Forestry and Fire Protection (CDF) as part of the NCWAP deliverables.   Therefore, it would seem that the website should match the findings of the NCWAP team, of which the Institute for Fisheries Resources (IFR) is a partner, as stated in the program description of the Report.  Furthermore, it is CGS’s understanding that the purpose of the KRIS Gualala website is to provide another avenue to present the scientifically based findings of the NCWAP assessment.  If this is the case, the KRIS Gualala website should be in agreement and compatible with the NCWAP findings rather than presenting information and conclusions that are not supported by the most complete set of data. 

 

Previous CGS comments on the KRIS Gualala database were recorded in a letter from Mr. Steve Sterling to Mr. Patrick Higgins dated March 15, 2002.  It appears that several of those comments were not adequately addressed in the current version of the KRIS Gualala website.  Several examples of comments that were not adequately considered are presented below.  The original CGS comments are first in bold face type, followed by the KRIS response in standard type, and then followed by CGS’s rejoinder to the KRIS response in italics:

 

The Technical Support Document (TSD) [prepared by the North Coast Regional Water Quality Control Board (NCRWQCB)] assumes that the geology is similar across the entire watershed (approximately 300 square miles).

 

The TSD Plate 4 is a geologic map indicating different terrain.

 

The response does not address the comment nor address the issue.  The geology across the watershed varies and should be reflected on the KRIS Gualala website.  It has been agreed that the NCWAP assessment has provided more data than what was available to the NCRWQCB during development of the Gualala TMDL.  The geology in the watershed is more accurately represented by the CGS maps and should be used in the KRIS Gualala website.  If the geologic map used in the TSD is included on the website, a qualifying statement must be added that indicates the assumption that the geology across the watershed is not similar and the newly completed CGS maps are more complete.  In addition, the licensed geologist responsible for preparing the TSD geologic map should be identified.

 

 

The TSD does not include mapping deep-seated landslides for development of the total maximum daily load (TMDL), which as a result, overlooks a potential major sediment source.

 

The TSD identified and estimated sediment from the active portions of large, deep-seated slides, although they did not map the larger non-contributing portions of these features.

 

This is not our understanding and this response is misleading. CGS staff has discussed the development of the TMDL with NCRWQCB staff.  Review of the TSD and discussions with NCRWQCB staff confirmed that the TMDL underestimated the area of deep-seated landslides.  The TSD assumed 10 percent of the Franciscan Central Belt formation were earthflows and mapped only shallow point slides throughout the watershed. Additionally, the NCRWQCB used the rate of 1.6 mm/year for non-earthflows and 48 mm/yr for earthflows to develop the TMDL. 

 

CGS’s findings identified active and dormant deep-seated landslides (earthflows, rock slides and composite slides) cover approximately 40 percent of the entire watershed, which indicates the total area of natural mass-wasting is notably underestimated in the TMDL.  Sediment rates from published literature for soil creep, uplift, earthflows and other mass wasting range from 300 mm to over 15 meters per year.  The NCRWQCB’s underestimation of deep-seated landslides and the use of rates less than most published values results in underestimation of natural mass wasting by approximately an order of magnitude or more.

 

 

The landslide mapping for the TMDL study was not performed by a California licensed geologist with the knowledge and experience necessary to properly conduct such investigations.

 

One needs an engineering geologist's license when rendering site-specific land use advice in California but not for mapping, doing a sediment budget, or using geologic information scientifically.

 

An inquiry to the California Board for Geologists and Geophysicists (Board) was made regarding if the above response was correct.  Mr. George Dunfield, Enforcement Manager for the Board responded in an email message dated June 06, 2002,  Mr. Higgins is incorrect and that the business and professions code does apply.  Consequently, any person who practices or offers to practice geology in the State and completes other tasks such geologic mapping of geologic materials is required to be licensed with the Board of Geologists and Geophysicists.  In addition, any such work completed upon which the public may be reasonably expected to rely shall be signed or sealed in accordance with section 7835 of the Act.”  The complete email message is included as an Attachment to this letter. 

 

Similar charts and discussion regarding sediment sources and their purported volumes of derived sediment have been removed from the Gualala Synthesis Report with consensus of all Gualala Team members.

 

The information stands as the best available for the Gualala, although CGS’s questions regarding TSD help understand the limits of its use. KRIS is science driven, not consensus driven. 

 

KRIS relies on the TSD as best available and does not acknowledge that there is more data available from CGS efforts.   CGS data and conclusions are based on evaluating deep-seated as well as shallow landslides, historically active as well as dormant landslides, which provides a more complete picture of mass wasting in the watershed.  Based on the more complete evaluations, CGS’s conclusions deviate significantly from the conclusions in the Gualala TSD/TMDL.  CGS maps and final geologic report (an appendix to the NCWAP assessment report) will be finalized with the NCWAP Gualala assessment report and available October 1, 2002.  CGS requests that our new maps, data and findings be included in the KRIS Gualala CD and website so that the public will have all data available for review.

 

 

TMDL charts should be removed from the KRIS Gualala CD or there should be a description of the limitations.

 

Reservations and qualifications offered by the CGS will be used in all captions or background pages where TSD data is discussed.

 

The KRIS Gualala should include the limitations of the TSD data and conclusions to provide a more complete picture of the data set.  The assumptions used including the geology and hydrology are homogenous across the watershed and that only

shallow land slides were mapped should be included.

 

It is recommended that the CGS relative landslide potential maps be incorporated into the KRIS Gualala CD (replacing the SHALSTAB maps) when they are completed.

 

Please supply electronic data and model parameters.

 

Maps and meta data will be provided when maps are finalized in October 2002.  

 

Specifically, how has model run been changed from a standard Dietrich et al. (1998) model? Layers will be added to KRIS Gualala Map project but SHLSTAB will be retained because it is scientifically valid and useful.

 

CGS does not agree with the statement.  Comments regarding SHALSTAB modeling from Technical Advisory Committee (TAC) on Forest Geology from the State Mining and Geology Board were provided with the March 15, 2002 comments.

 

Added CGS disclaimer on SHALSTAB to Background page.

 

The disclaimer should include a copy of the TAC comments.  SHALSTAB was used as a quality control check as well as other models in developing the relative landslide potential map.  SHALSTAB is based on slope and convergence using the DEMs.  It does not consider the geologic formation or address deep-seated landslides, which are significant factors in slope stability.

 

KRIS products should not be released until the CGS relative landslide potential maps are incorporated in the final KRIS products.

 

KRIS Gualala can add the CGS data as it becomes available.  What is the release date for the data?

 

CGS will release maps in time to be incorporated into the final Gualala report due on October 1, 2002.

 

“The parameter poor, topography-based SHALSTAB program falls well below the current standards of geologic/geotechnical practice.”

 

It does not meet standards for site-specific land use decisions but serves well for risk assessment and as a reconnaissance tool at a watershed scale, which is how it is used in KRIS.

 

This is not correct.  SHALSTAB misses several areas in the Gualala River watershed on a regional scale.  For example, SHALSTAB and the CGS Relative Landslide Potential Map are very different in the southeastern portion of the watershed where the underlying geologic formation is Central Belt Franciscan (includes belts of mélange), but the slopes are not steep.  These areas have slope stability problems that SHALSTAB does not indicate.  (This is easily seen on a regional scale when comparing the slope stability runs of the EMDS model using the SHALSTAB input (early runs as placeholders) and then later runs with the relative landslide potential data).  The limitations of the SHALSTAB modeling are not included in the KRIS Gualala and the SHALSTAB results can be misleading and/or misused.

 

If the KRIS data base is released in its current form with out including the limitations regarding SHALSTAB and the recent CGS sediment calculations, the opportunity for geologic data and conclusions to be misconstrued and misused by community members, watershed stakeholders, and local and regional agencies is greatly increased.

 

Policy question.  Can’t we trust the public (and other agencies) to participate in an informed dialog?

 

Presenting incomplete information and not including the limitations of existing data and conclusions (e.g. TMDL, TSD and SHALSTAB) does not provide the public with a complete foundation to make informed decisions.  Providing only part of the information is not scientifically based and can be misleading and biased.

 

 

In the spirit of completeness and providing available data and conclusions to the public, CGS requests that the new maps, geologic report and associated data compiled and developed under NCWAP be incorporated in the KRIS Gualala website.  Even though there are differing conclusions, additional information and data will broaden the baseline information and can enhance the decision-making ability in regard to land management activities. 

 

If you have any questions or comments please contact me at 916-322-2588.

 

 

Sincerely,

 

 

Stephen C. Sterling, CEG

Supervising Geologist