Rules and Regulations for Dam Safety and Dam Construction Rules - PowerPoint PPT Presentation

Rules and Regulations for Dam Safety and Dam Construction Rules Hearing Presentation 1313 S herman S treet, Rm 814 Denver, CO November 6, 2019 Bill McCormick, P .E., P .G. and Jason Ward, PhD, P .E. Colorado Dam S afety

Out line for Discussion • Introductions • The Rulemaking Process • S ummary of S ignificant Rule Changes • Questions and Discussion

RULES

Statutory Authorities CRS Title 37 Article 87 • 37-87-105-Approval of Plans for Reservoirs • Make and Maintain Rules and Regulations (The Rules) • Review and Approval Authority for; New Dams, Alteration, Modification, Repair and enlargement of existing dams • 37-87-107- S afet y Inspect ions-Amount of Wat er t o be S t ored • Inspections • Determination of S afe S torage Level

Dam Safety Rules Revision Timeline Dec. 1 – Rules Revision Committee formed Nov 19 – Dam S afety Meeting Dec. 17 – Conf. Call #1 Workshop #1 (breakout sessions) Jan 21 – Committee Meeting Workshop #0 Feb. 4 – Conf. Call #2 Feb. 11 – Conf. Call #3 2014 2015 May. 12 – Dam S afety Meeting Apr. 13 – Conf. Call #5 Mar. 10 – Hydrology Conf. Call #1 Mar. 2 – Conf. Call #4

Dam Safety Rules Revision Timeline Jan 5 – Meeting with AG Paul Bennington Feb 1 – Workshop #2, FEB2017_DRAFT Jan 27 – JAN2016_DRAFT Feb. 2 – Conf. Call #6 Feb. 2 – Conf. Call #6 April – Dam S afety Meeting Workshop #3, APR2017_DRAFT May – Dam S afety Meeting MAY2016_DRAFT May – Dam S afety Meeting MAY2016_DRAFT 2016 2017 Dec 20 – Conf. Call #7 Dec 14 – DEC2017_DRAFT Nov – Dam S afety Meeting Dec 4-6 Geotechnical NOV2016_DRAFT Workshop, C. S prings Nov – Dam S afety Meeting Workshop #4, NOV2017_DRAFT

Dam Safety Rules Revision Timeline Feb 1 – Workshop #5 , w/ AG Andy Nicewicz Jan 1 - April 30 – S takeholder Input FEB2018_DRAFT Mar 6 – MAR2018_DRAFT Apr. 26 – Workshop #6 , S alida April 30 – Enter Rulemaking APR2018_DRAFT Aug 1 – New Rules Effective Date May – MAY2018_DRAFT 2018 2019 Nov 31 – NOV2018_DRAFT – “ Final Draft” Nov – Dam S afety Meeting, Workshop #7 NOV2018_DRAFT

Proposed Dam S afet y Rules Proposed Rules and Comments Maintained Colorado Dam S afety website: http:/ / water.state.co.us/ damsafety/ dams.asp

Dam Safety Engineer - Rule Makers

Philosophy • Process followed Executive Order 2012-002 Regulatory Efficiency Reviews: • Is necessary and does not duplicate existing rules; • Is written in plain language and is easy to understand; • Has achieved the desired intent and whether more or less regulation is necessary; • Can be amended to reduce any regulatory burdens while maintaining its benefits; and • Is implemented in an efficient and effective manner, including the requirements for the issuance of any permits or licenses.

Major Steps • Editorial revisions – “ Wordsmithing” • Additional Definitions (Rule 4) • Deleted and or Combined Rules • Reorganization (moving and/ or combining) to improve flow and reduce redundancy

S t akeholder Engagement and Meet ings - 2019 • S tatewide email announcements beginning January 15 • Colorado S prings – February 22 • Denver – March 19 • Greeley – March 21 • ACEC Denver – March 29 • Glenwood S prings – April 2 • Grand Junction – April 3 • Durango – April 9 • Alamosa – April 10 • Craig – April 24 • UDFCD Denver – May 14 • S tatewide email announcing formal process S ept 25

Definitions – Rule 4 • 4.2 – Annual Exceedance Probability (AEP) • 4.6 – Dam - Jurisdictional and Non Jurisdictional only. No size, i.e. “ minor, small, large” distinctions • 4.15 – Hydrologic Hazard • 4.23 - Potential Failure Mode (PFM)

Significant New Rules – Rule 4 4.24 – Potential Failure Mode Analysis (PFMA) 4.29 – Risk

Significant New Rules- Rule 5 Rule 5 - Determination of S afe S torage Level • Moved to beginning of rules for clarity • 5.2 - Methods of determining safe storage level • S afety Inspections • Use of PFMA in addition to safety inspection • 5.3 – S torage Restrictions • 5.4 - Review of Hazard classification

CDSE Guidance Docs - Likelihood and Confidence 16

PFMA - Actions

Pot ent ial Failure Mode Analysis (PFMA) Tools Guidance Documents http:/ / water.state.co.us/ damsafety/ dams.asp

Significant New Rules - Rule 6 Rule 6. – Design S ubmittal • Pre-design Meeting • Electronic processes • Consequences (up front inundation map) • Engineer’s qualifications statement and affidavit 19

Significant New Rules – Rule 7 • 7.1- Design Requirements – New and existing. S ilent on “ grandfathering” • 7.2 – Inflow Design Flood (IDF) for S pillway sizing • Risk-Based Approach for High Hazard dams • Frequency Approach for S ignificant and Low hazard dams • S ignificant – 1/ 1000 (0.1% AEP), Low – 1/ 100 (1% AEP)

RCEM PAR to LOL – Guidance Doc • Population at Risk (PAR) determined from inundation mapping analysis – Existing model • Loss of Life (LOL) Calculated using PAR and US BR RCEM • S pillway sizing only NOT Hazard Classification • Recognizes and addresses differences in Risk between High Hazard dams

RCEM PAR to LOL • Fatality Rate vs DV – adequate warning

What does it mean? Black Hollow Reservoir Example • PMP vs PF

Comparison Example

Climate Change Considerations

Warmer Average Temperatures

Key Science, Likelihood and Confidence • The deterministic PMP approach explicitly optimizes the storm environment of the controlling historical storms • Temperature controls the water-holding capacity of the atmosphere; i.e., warmer air holds more water. • Temperature increase: very high likelihood, strong confidence • Maximum precipitable water/ moisture increase: very high likelihood, strong confidence • Physics - A warming of 1 degree F leads to a roughly 3.5% increase in that water-holding capacity; 2 degrees F leads to a 7% increase.

Proposed New Rule 7.2.4 Atmospheric Moisture Factor. All rainfall depth estimates calculated by means acceptable to the S tate Engineer shall be multiplied by a factor of 1.07 prior to calculating runoff to account for expected increases in temperature and associated increases in atmospheric moisture availability over the 50-year period 2020 to 2070.

Significant New Rules – Rule 7 • Rule 7.3 – S ubsurface Investigation Plans • Rule 7.4 – Embankment Design • Explicit protection for internal erosion failure modes • Rule 7.5 – Concrete Dams • S tandards-based • Rule 7.6 – S eismic Design Requirements • S tandards-based • Rule 7.8 – S pillway Design • S tarting water surface elevation considerations

Significant New Rules • Rule 8 – Describes requirements for during construction and proj ect acceptance (Combined previous Rules 9 and 10) • “ Design” Change Order • Rule 9 – Dam removal and dam Breach • Rule 10 – Non-j urisdictional dams • Rule 11 – General Maintenance, Ordinary Repairs and Emergency Actions • Notification of large outlet or spillway releases to reduce downstream hazards during operations

Significant New Rules • Rule 12 – Dam owner’ s Engineer performed inspections • Rule 13 - Owner Responsibilities • Dam Observation and Monitoring Plans • EAP Notifications - Emergency Response Teams • Rule 14 – Exempt S tructures • Rule 15 – Restrictions on Recreational S tructures • Rule 16 – Waiver or Delay of Enforcement of Rules by the S tate Engineer • Rule 17 – Appeals • Rule 18 - Rules by Reference

Significant New Rules • Rule 18 - Rules by Reference • Reference publication dates • Rule 21 – Basis and Purpose

Guidance Document s • Proj ect Review Guide (updated) • Hazard Classification (Updated) • Dam Breach Analysis (updated) • Use of CDS E Tools (new) • S ubsurface Investigation Plans (new) • REPS Use Guidance (new) • Hydrologic Hazard Analysis (new) • RCEM (existing, US BR) • Rule 6.5 Dam Engineer Affidavit (new)

Quest ions?