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

Bill McCormick, P .E., P .G. and Jason Ward, PhD, P .E. Colorado Dam S afety

Rules and Regulations for Dam Safety and Dam Construction Rules Hearing Presentation

1313 S herman S treet, Rm 814 Denver, CO November 6, 2019

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

2014

• Dec. 1 – Rules Revision Committee formed

2015

Jan 21 – Committee Meeting Workshop #0

• Feb. 11 – Conf. Call #3
• Feb. 4 – Conf. Call #2
• Mar. 2 – Conf. Call #4
• Mar. 10 – Hydrology Conf. Call #1
• Apr. 13 – Conf. Call #5
• May. 12 – Dam S

afety Meeting Nov 19 – Dam S afety Meeting Workshop #1 (breakout sessions)

• Dec. 17 – Conf. Call #1

Dam Safety Rules Revision Timeline

2016

Jan 5 – Meeting with AG Paul Bennington

• Feb. 2 – Conf. Call #6

Jan 27 – JAN2016_DRAFT May – Dam S afety Meeting MAY2016_DRAFT Nov – Dam S afety Meeting NOV2016_DRAFT Dec 20 – Conf. Call #7

2017

Feb 1 – Workshop #2, FEB2017_DRAFT

• Feb. 2 – Conf. Call #6

April – Dam S afety Meeting Workshop #3, APR2017_DRAFT May – Dam S afety Meeting MAY2016_DRAFT Nov – Dam S afety Meeting Workshop #4, NOV2017_DRAFT Dec 4-6 Geotechnical Workshop, C. S prings Dec 14 – DEC2017_DRAFT

Dam Safety Rules Revision Timeline

2018

Feb 1 – Workshop #5, w/ AG Andy Nicewicz FEB2018_DRAFT

• Apr. 26 – Workshop #6, S

alida APR2018_DRAFT Mar 6 – MAR2018_DRAFT May – MAY2018_DRAFT Nov – Dam S afety Meeting, Workshop #7 NOV2018_DRAFT Nov 31 – NOV2018_DRAFT – “ Final Draft”

2019

Aug 1 – New Rules Effective Date April 30 – Enter Rulemaking Jan 1 - April 30 – S takeholder Input

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

16

CDSE Guidance Docs - Likelihood and Confidence

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

19

Rule 6. – Design S ubmittal

• Pre-design Meeting
• Electronic processes
• Consequences (up front inundation map)
• Engineer’s qualifications statement and affidavit

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?