stateofcaiifornia · pdf fileproposed emergency regulations —inundation maps note all...

STATEOFCAIIfORNIA-OFfiCEOfAQMiNt5TRA7fttELA4l+ f$eE II'l3f!'EtCt10I1S Oil

N~'~IC~ I~U$C.ICATIQN/RECULATIC~11#S ~Cl~Q11~ISSfiCa~~ reverse

OAS FILE HaTIGE FILE NUMBER. REGt1tATORY ACftON NUAABER EddERGENCY NUMBER

NUMBERS Z. ~ Q ~ ,,-• i V ~7 7 ""° ~ ~~

For use by Office of Administrative Law {QAL} only

~1`~ ~"4 ,~Q - r~ ~~ b~ g

__

1. ~ ~;~'i ~ r''ii- ~

idt3TICE REGU1.61T1~lS

I16~1CX WITH ItULEMAKiNGAUTNORITYDepartment of Water Resources

For use by Secretary of State only

A. PIJBLICATIt3N ~F NOTICE (Complete for pablis~tiort in 4~otiee Register)

1. St18JEGT t7F NOTECE TITLE(57 FIRST S

Pe Propesad 4.Mry Artinrs ~ ~4'~

DAL USiE .~..,~. ~-..,,r ~... ~a~ ~ ~..~ ~~.~~~en,..,n~o~,. ..

ONLY ~ Aar a.` ❑ ~PP~avea as ~ o~aaarovecuSubmitted Motltt~d Witlidrswtt

B. 5llBMISSIOM Of RECtiLATlf)~1tS ECott~ttp[ete when submitt€ctg cegu~atians~

1a. SUBJECt OF REGUlATION(S} "Eb. ALL PREVEOt1S RELATEQ {}AL REGUtATOftY ACTION NUMBERS}

Inundation Maps.

Z, SPECIFVCALIfoRNIAC06EgFREGULATiONSTITLEfS~ANO5EEitON{S) (InciwifmgRifle26,iiEo~cicsralatedy

S~~~I~td(S) APFEC~'ED a o

(Lisa all section numt~er(sl 335, 335.2, 335.4, 335.6, 335.8, 335.1 t}, 335.12, 335.14, 335.1 fi, 335.18, 335.2(}

inciivEduaOly. A~4ach aat ry `

........additional slse~t if needed.TITLE(Sj REpEAI.

2~

3. TYPE Of FIGNG

Regular Rulemaking EGov ~ Cerkiffeate oftompiFance: Ft~e agency officer narxaed d Emergency Readapt (~v~ i—( Changes Without RegulatoryCgde §t 1346) be(c~w certifies tfiat this agency carrtpi#ed witi~ the Code. §t 1346.1(h}) ~—~ :Effect (Cat. Code Regs., title

!"'I Resu6miCtai of disapproved or provisions of Gov. Cade §§ 71346.2-11347.3 either i, 41 ~}tJ withdrawn nonemerger~cY beforethe eme€gency reguiacion was adopted ar

filing (Gov. Cade §§t 13493, within the time period requieed 6y sta[ute. ~ FEte & Prteec ~ print Qnly

11344.4)Emergenc}r(Gov.~ode, ❑ Resubmittalafdisapprovedorwi[hdrawn ~ {~~f(~p~i{~,a~r

§ t 1346.1 tb)) emergency fliEng tGov. Code. § > > 3a6.~ l

4, AIL BEGIt~tINGAND£P1DtNGDATF50FRVAlLR81LitYOFMODiFiEDF~GtfEAT1lNESANDlORPAATERIALAF}DEOTQTHERU€ENfA~NGFELE(Eaf. CodeRegs.tftlei,~44 aru3Gov.Code ¢11347.1)

S. EFFECTNE DATE OF CHANGES CC,ay. Cede, §§ 17 343.4. t T346.I tdl, CaE. Cade Begs., tine t, 41 ~ a

Q Effective 3enuary 1. April 1, JuIY i, a ~ Effective ott f~irtg month ~[ §tom Ctranges+A7iti~ovt EffectiveQctobet t (Gov. Ct §t1343:4{a7) ~- - c SecretaryotState t_t Re9ulacory effect ~ othertSpeGfY)

6. CHEGK IF THESE REGIJl.ATIONS F2E~UIRE NOTICE Tp, OR REVIEMt, CONSULTATfGtN, APPROVAt.OR CONCURRENCE 6Y, FtNOTFlER AGENCY OR ENTITY

Department of Ftnartce (farm STD. 349} {SAttit §666Q} ~ ~~~r Political Practices Commission ~ State Fire Marshal

Othef(5pecify}

7. GONTA6T PERSON 7ELEPHQhlE Nt~tBER FAX PlUA48ER (Option~j E-MAIL AQDRESS {pp6atal~

Michael Wa~ganer (9'16} 227-98ttU [email protected]

8. 1 ee~tify that the attaclhed copy ofthe ~°egui~~ian(s) is ~ ~re~e ~n~ e~rr~e~ ~ap~ For use by office of Administrative Law (t3AL} only

of Cite regulat ron(s} ideett$ied an tFeis farm. that the information s~secifie~i ~n tS~~s foetn

is true a nd co rrect, and th~#~,~m the head of the agency taking this action,

or a e~e~si~nee.~ft~e hea}d'ot jhe agency, and am authorized to make tE~~s c~rt~ieatian.

? ~.,.

Grant~Davis, Director •~~-~'.~~

Proposed Emergency Regulations —Inundation Maps

NOTE All of the proposed regulation te~rt is to be added to the California Code ofRegulations.

- California Code of Regulations

Title 23. Waters

Division 2. Department of Water ResourcesChapter 1. Dams and Reservoirs

Article 6. Inundation Maps

§ 335. Scope of Regulations

Inundation maps shall be prepared for dams and critical appurtenant structures regulatedby the state, except dams classified by the department as low hazard as described inSection 335.4. The regulations in this article apply to inundation maps and supportingtechnical studies necessary to develop the maps. Owners are responsible for preparing andsubmitting these documents to the department.

Note Authority cited Sections 607$ and 6162, Water Code. Reference Sections 6002, 6160,6161, Water Code.

§ 3362. Definitions

For purposes of this Article, the terms listed below shall have the meanings noted

(a) "Breach" refers to a sudden opening through a dam system that drains the reservoir.

(b) "Breach elevation" refers to the elevation of the water in a reservoir at full reservoirconditions.

(c) "Breach time" refers to the modeled time elapsed from initial dam failure to total damfailure.

(d) "Critical appurtenant structure" refers to a man-made barrier or hydraulic controlstructure that impounds the same reservoir as the dam and is 25 feet or more in height, asmeasured from the upstream toe to the maximum water storage elevation; impounds aminimum of 5,000 acre-feet of water at full reservoir conditions; or has the potential toinundate downstream life or property, including but not limited to emergency spillways,gated spillways, and saddle dams.

Oct. 2,_2017.

1


A critical appurtenant structure may contain multiple water-barrier features, including but

not limited to gates, flashboards, and concrete monoliths. Power system penstocks, lined

spillway chutes, and low level outlets whose failure would not exceed the downstream

channel capacity are not considered critical appurtenant structures as they pertain to

inundation maps.

(e) "Critical facilities" refers to lifeline infrastructure and facilities including but not limited

to schools, hospitals, skilled nursing facilities, major roads, public water and electric

utilities, and communication infrastructure, as described in Section 8589.5 of the.

Government Code.

(fJ "Cross-section" refers to a linear representation perpendicular to a watercourse and its

adjacent floodplain, capturing the topography perpendicular to the flow direction.

(g) "Dam system" refers to a dam and all critical appurtenant structures that impound the

same reservoir.

(h) "Deflood time" refers to the time elapsed from the flood wave arrival time until water at

the measured location recedes to within one foot of its preflood water elevation.

(i) "Dynamic routing" refers to hydraulic flow routing based on the shallow water equations

to compute changes in discharge, velocity,. and stage with respect to time at various

locations along a watercourse. The most common form of the equations is the Saint-Venant

..equations.

{j) "Failure scenario" refers to the modeled simulation of a complete or partial failure of a

dam system, including a breach, which results in an uncontrolled release of water.

(k) "Flood surcharge" refers to the volume in a reservoir above the maximum certified water

storage elevation resulting from a storm event.

(1) "Flood wave arrival time" refers to the elapsed time from the initiation of the failure

scenario until the arrival of the leading edge of the flood wave comprising a one (1) foot rise

above the ground elevation or water surface elevation before the failure scenario.

(m) "Freeboard" refers to the vertical distance between the lowest point along the top of a

dam, dike, berm, levee, or other similar feature and the surface of the water contained

therein.

(n) "Full reservoir conditions" refers to the maximum water storage elevation authorized in

the department's Certificate of Approval for the dam.

Oct.2..2017 _

2


(o) "Hydraulic model" refers to a simulation of conveyance of water through a watercourse.

(p) "Hydrologic model" refers to a simulation of watershed processes such as precipitation,infiltration, and runoff. Hydrologic models perform simplified forms of dynamic routing.

(q) "Inundation area" refers to the area that would experience a rise in water surfaceelevation of at least one (1) foot as the result of a failure scenario.

(r) "Inundation map" refers to a map showing the area that would result in flooding from afailure scenario.

(s) "One-dimensional model" refers to a numerical hydraulic model in which variables suchas velocity and depth vary in one direction along a watercourse.

{t) "Peak flow" refers to the maximum rate of water discharge.

(u) "River mile" refers to the distance from a fined point along a watercourse, measuredalong the thalweg.

(v) "Sequential dam failure" refers to a failure scenario of an upstream dam system that

results in the failure of one or more downstream dam systems.

(w) "Storm induced failure" refers to a failure scenario in which the extent of the

inundation area is greater than that of asunny-day-failure-scenario. - - - - --

(~ "Sunny day failure" refers to a failure scenario of the dam system during full reservoir

conditions with non-flood season inflow.

(y) "Thalweg" refers to the line connecting the lowest point of a watercourse.

(z) "Toe" refers to the junction of the slope of a dam or critical appurtenant structure with

the natural ground surface.

(aa) "Two-dimensional model" refers to a numerical hydraulic model in which variables

such as velocity and depth vary in two directions along a watercourse.

(bb) "Watercourse" refers to a stream or open conduit, including but not limited to canyons

and floodplains.

Note= Authority cited Sections 6078 and 6162, Water Code. Reference Section 8589.5,

Government Code; Sections 6002, 6002.5, 6004.5, 6005, 6008, and 6161, Water Code; FEMA

Oct. 2 2017 3


2013, Federal Guidelines forinundation Mapping ofFlood Risks Associated witb Dam

Incidents and Fazlures (FEMA P-946).

§ 335.4. FIazard Potential Classification

The department shall classify the public safety risk of all state jurisdictional dams, in a

manner consistent with FEMA 333 (2004), as follows

(a) Low Hazard Potential. Dams assigned the low hazard potential classification are those

where failure or mis-operation of the dam system would result in no probable loss of human

life and low economic and/or environmental losses. Losses are expected to be principally

limited to the owner's property.

(b) Significant Hazard Potential. Dams assigned the significant hazard potential

classification are those dams where failure or mis-operation of the dam system would result

in no probable loss of human life but can cause economic loss, environmental damage,

disruption of lifeline facilities, or other significant impacts.

(c) High Hazard Potential. Dams assigned the high hazard potential classification are

those where failure or mis-operation of the dam system will probably cause loss of human

life.

(d) Extremely High Hazard Potential. Dams assigned the extremely high hazard potential

classification are dams that would otherwise be classified as high hazard dams, but where

failure or mis-operation of the dam system would .probably cause considerable loss of

human life and would affect an inundation area with a population of 1,000 persons or more,

or where critical facilities could be impacted.

Note Authority cited Sections 6078 and 6162, Water Code. Reference Section 6002.5,

6009, 6160 and 6161, Water Code; FEMA 2004, Federal Guidelines for Dam Safety: Hazard

Potential Classification System for Dams (FEMA 333).

§ 335.6. Inundation Map Updates

The owner of a dam shall update all inundation maps for the dam system under each of, but

not limited to, the following circumstances

{a) The department determines there is a .significant change in .the dam or critical

appurtenant structure.

Oct. 2 201'7 _ 4


(b) There is a significant change in downstream development that involves people and

property.

(c) The department changes the hazard classification of the dam.

(d) No less frequently than every 10 years.

Note Authority cited Sections 6078 and 6162, Water Code. Reference Section 6006, 6007,

and 6161, Water Code.

§ 335.8. Civi]. Engineering

Inundation maps and technical studies shall be prepared by, or under the direction of, a

civil engineer who is registered pursuant to California law and authenticated as provided in

the Business and Professions Code, Division 3, Chapter 7 commencing with Section 6700.

Nate Authority cited Sections 6078 and 6162, Water Code. Reference Section 6161, Water

Code; Section 6700, Business and Professions Code.

335.10. Reporting Standards

Inundation maps and. technical studies prepared in accordance with this Article shall

utilize the following standards and conventions, unless otherwise indicated

(a) Reservoir storage and other water volumes shall be reported in acre-feet.

(b) Water discharge shall be reported in cubic feet per second.

(c) Geographic locations shall be reported in California Coordinate System or Universal

Transverse Mercator coordinates relative to NAD83. Coordinates shall be specified

commensurate with the precision of the analysis.

(d) Elevations shall be reported in feet above a specified vertical datum such as NAVD88 or

NAVD29. Elevations may also be reported relative to an established local datum.

(e) Geospatial data shall be submitted in NAD 1983 Teale (California) Albers projection,

with the units specified.

Oct. 2 2017 _ 5


Note Authority cited Sections 6078 and 6162, Water Code. Reference Section 6161, Water

Code.

§ 335.12. Technical Study

A single technical study shall be prepared for each dam system for which inundation mapsare required.

(a) Study contents. The technical study shall include the following

(1) The name of the dam, department dam number, national dam ID number, and name ordescription of any critical appurtenant structures.

(2) The location of the dam and all critical appurtenant structures.

(3) The name and location of cities, towns, counties, and any populated area that could be

affected by a failure scenario.

(4) A brief narrative of the hydrologic, meteorologic, and topographic features of the

watershed, dam site, and downstream areas.

(5) An engineering description of the dam, including the type of construction (e.g., earth,rock, or concrete). Include a description of the features comprising each critical appurtenant

structure (i.e., a description of all the gates and concrete structures comprising a gated

spillway structure).

(6) Elevation of the crest and upstream toe for the dam and each critical appurtenant

structure. Report the elevation of the downstream toe of the dam.

(7) A reservoir storage capacity curve that shows the relationship between reservoir

elevation, surface area, and volume from the base of the reservoir to the dam crest.

(8) A spillway rating curve that shows the relationship between stage and discharge.

(9) The type of terrain data used, including any modifications made to the terrain.

(10) A summary of the modeled failure scenarios for the dam system.

(11) The modeling methodology, the reasons for its use, and the name, version, release date

and author of the modeling software. Report all assumptions, failure parameters,

Oct. 2 2017 _ 6


calibration and sensitivity analyses of the model, including the model's response to changes

made to the roughness or other friction coefficients. Report modifications made to stabilize

the model or accelerate its computational runtime, and the effects such modifications have

on the modeled inundation results. Describe known limitations of the modeling method

utilized. Provide justification for determining the downstream extent of the inundation

boundary.

(12) Digital files comprising the following for each failure scenario

(A) A vector file of the inundation area boundary.

(B) Raster files of the flood wave arrival time, maximum depth, peak velocity, and deflood

time.

(13) The department may request additional information during the course of its review.

fib) Modeling Requirements.

(1) A two-dimensional, open channel, unsteady flow, hydraulic model shall be used to

evaluate each failure scenario for a dam system, except as described below. The model must

be capable of performing dynamic routing to approximate the temporal and spatial changes

in inundation magnitude and extent.

(2) A one-dimensional hydraulic model may be used that is capable of computing spatial

and temporal changes to water surface elevation, velocities, and flows at each cross section.

A one-dimensional model may be used only in the following circumstances

(A} To simulate levee overtopping as a subcomponent of the two-dimensional model of the

failure scenario

(B) Where the flood wave would be confined to a canyon or narrow watercourse in which the

direction of flow is dominantly in the downstream direction.

(3) Upon approval of the department, the owner of a significant hazard dam may use a

hydrologic model, rather than a hydraulic model, if the dam impounds less than 100 acre-

feet of water and the flood wave produced by the failure scenario would be confined to a

canyon or narrow watercourse in which the direction of flow is dominantly in the

downstream direction.

(4) Each model shall utilize the best available terrain data, consisting of the finest

resolution discretization available.

Oct. 2~ 2017 _

7


(c) Failure Scenarios. A sunny day failure condition is required for each dam and critical

appurtenant structure. If a storm induced failure condition is modeled for a dam system,

that failure scenario may be submitted in lieu of a sunny day failure scenario.

Each failure scenario shall employ a complete and nearly instantaneous loss of the dam or

critical appurtenant structure, and utilize breach parameters as described in FEMA P-946(2013). The geographic extant of the model simulation shall terminate in accordance with

FEMA P-946 (2013). Failure scenarios shall be modeled as follows

(1) For gated critical appurtenant structures, such as a spillway with multiple radial gates,the failure scenario shall consist of the complete failure of all gates together with the

concrete control section breached to the .upstream. toe.

(2) A sequential dam failure scenario is required for an upstream dam system that causes

the failure of one or more downstream dam systems, as described in FEMA P-946 (2013). A

sequential dam failure scenario shall employ an overtopping failure mode for all

downstream dam systems impacted by the routing of the flood wave downstream. The

owner of the upstream dam system is responsible for preparing the sequential failure

scenario.

Note Authority cited Sections 6478 and 6162, Water Code. Reference Section .6161, Water

Code; FEMA P-946 (2013).

§ 335.14..Inundation Maps

Inundation maps shall be prepared for each failure scenario to satisfy the FEMA P-946

(2013) and the requirements of this section.

(a) Temporal contours. Two separate inundation maps shall be prepared for each failure

scenario, with contours depicting time increments appropriate for the failure scenario for

flood wave arrival time and deflood time.

(b) Depth grid. All inundation maps shall depict the entire inundation area with discrete

categories of maximum flood wave depths, with a legend showing each depth range. The

opacity of the maximum flood wave depth layer shall be adjusted to display the underlying

base map.

(c) General information. Each inundation map shall contain the following general

information

(1) The name of the dam, the department's dam number, the national dam ID number, and

the county in which the dam is located.

Oct. 2, 2017 _ _

8


(2) The failure scenario. If a storm induced failure scenario is depicted, the return period

shall be reported on the inundation map.

(3) The map background with suitable aerial imagery.

(4) Callouts identifying the location of the dam, all critical appurtenant structures, and all

critical facilities affected by the failure scenario. The downstream watercourse and flood

control features, such as dams, levees, weirs, pumps, and control structures shall be

labeled.

(5) The identity of any jurisdictions, including boundary delineations or place marks

identifying the city, county, or other governmental agency jurisdictional boundaries affected

by the inundation area.

(6) An arrow indicating north.

(7) An appropriate scale bar and the stated map scale.

(8) Vertical elevation datum.

(9) Map collar information, including horizontal reference grid ticks.

(10) An index-showing the-relationship-of the -map -sheet-to the other map sheets if the map

has multiple sheets.

(11) The date of preparation of the map.

(12) The signature, seal, and licensed civil engineer number of the engineer responsible for

preparing the map.

(13) All features on maps shall be clearly labeled with text boxes and legends, as

appropriate.

(14) A statement that the information shown is approximate and should be used as a

guideline for emergency response and preparation purposes.

(15) A statement confirming the inundation map meets all applicable state and federal

standards and has been prepared in consideration of all potential downstream hazards by a

licensed civil engineer.

Oct. 2 ..2017... _

9


(d) Map Layout. Each of the inundation maps shall be printed on 11X 17 inch or 24X36 inch

paper, with a minimum resolution of 300 dots per inch. All inundation maps shall apply an

appropriate map scale as described in FEMA P-946 (2013). For failure scenarios with a

large. inundation area, each inundation map may comprise more than one sheet.

Note Authority cited Sections 607$ and 6162, Water Code. Reference Section 85$9.5,

Government Code; Sections 6160 and 6161, Water Code; FEMA P-946 (2013).

§ 335.16. Submission of Inundation Maps and Technical. Study

The owner of a dam shall submit inundation maps and the supporting technical study to

the department as specified below

(a) An electronic color copy of each new and revised inundation map in portable document

format (PDF extension). If practical, two hard color copies of each inundation map should

also be submitted.

(b) Technical Study Two hard copies and an electronic copy including digital content.

Note Authority cited Sections 6078 and 6162, Water Code. Reference Section 6161, Water

Cade.

§ 335.18. Department Review and Approval.

(a) The department shall evaluate each. inundation map and technical study that is

submitted for consistency with the requirements of this article and shall notify the dam

owner in writing that the map and study have been approved, are incomplete, or are

disapproved and the reasons therefor, as follows

(1) Approved. The department has evaluated the inundation maps) and technical study

and determined that they satisfy the requirements of this article.

(2) Incomplete. The department has evaluated the inundation maps) and. technical study

and determined that one or both do not satisfy the requirements of this article as a result of

minor problems identified by the department. A dam owner shall have 60 calendar days

from the time the department provides a notice of incompleteness to remedy any

deficiencies and submit the corrected map and study. The department may extend this

deadline if the map and study have been submitted more than 180 days before the deadline

. _imposed by Section 6.161 of the Water Code for submission of an emergency action plan.

Oct. 2, 2017......_

10


(3) Disapproved. The department has evaluated the inundation map and technical studyand determined that one or both do not satisfy the requirements of this article due tounresolved problems associated with an incomplete submittal. When an inundation map ortechnical study is disapproved, the dam owner shall submit a new map and technical studythat satisfy this article.

b) Inundation maps submitted to the department for review by January 1, 2018, shall beevaluated for consistency with the FEMA P•946 (2013).

Note Authority cited Sections 6078 and 6162, Water Code. Reference Section 8589.5,Government Code Sections 6161 and 6431, Water Code. FEMA P-946 (2013).

§ 335.20. Public Availability of Inundation Maps

The department shall post copies of approved inundation maps on the department'swebsite.

Note Authority cited Sections 6078. and 6162, Water Code. Reference Section 6161, Water

Code,

Oct. 2 201.7

. 11

FINDING OF EMERGENCY

The Department of Water Resources (department) finds that an emergency exists, pursuant toWater Code Section 6162, which calls far immediate action to avoid serious harm to the public:peace, .health .and safety,. or general welfare.

Water.Code Section 6161 (a) requires owners of state jurisdictional .dams, except thoseclassified as lowhazard, to prepare and submit inundation maps for department approval. Theproposed emergency .regulation is needed to clarify and make specific the details. of thisrequirement. Water Code Section 6161(a)(3) requires owners to develop and submitEmergency Action Plans (EAPs) based. on department-approved. inundation maps. Failure totake :immediate action will delay inundation map and EAP submittal, potentially endangeringpublic .safety. This could lead to time delays in evacuation and. potential loss of life in the eventof a dam emergency.

Background

The Oroville spillway incident that began on February 7, 2017 called attention to the need forinundation maps and emergency action plans (EAPs) for dams and critical appurtenantstructures. During the emergency, an evacuation was ordered because failure of the emergencyspillway was considered imminent. Before the incident, an inundation map and associated EAPexisted for the potential failure of Oroville Dam.. However, an inundation map and: EAP did. notexist for the potential failure of the emergency spillway, which is considered a criticalappurtenant structure. This lack of critical information led to confusion regarding areas thatrequired evacuation during the emergency.

The state legislature passedSB92 that went-:into effect on July 1, :2017 and added new sectionsto the Wa#er Code requiring owners of all state jurisdictional dams, except law hazard dams, toprepare. inundation maps. Before the SB92, there were no requirements to develop inundationmaps.#or many state jurisdictional dams, all critical appurtenant structures, or #o updateinundation .maps. The Oroville spillway incident highlights the need for inundation maps andEAPs to be prepared and submitted. for all dams and their cri#ical .appurtenant structures, exceptdams. classified as low hazard. Dams classified as low hazard are. not expected to cause anyloss of life should they fail, and any potential downstream .impacts .are .expected to be confinedto,the dam owner's. property.

Specific Facts Showing Existence of Emeraencv and the tVeed for Immediate Action

Water Code Section 6162 states that any regulations .promulgated. pursuant to Article 6 relatedto inundation maps shall be deemed to be an emergency. and .are. necessary for the immediate.preservation of the public peace, health and safety, or general welfare.

The Oroville spillway incident called attention to the urgent need for inundation maps and EAPsfor dams and critical appurtenant structures. Water Code Section 6161(d) requires owners ofstate jurisdictional dams, except those classified as low hazard, to submit inundation maps andEAPs prioritizing dams by highest hazard. Dams classified as "extremely high" hazard arerequired to prepare and submit EAPs by January 1, 2018.

The dam owners' ability to meet the statutory deadlines is contingent upon the swift approval ofthese. emergency regulations. Once the emergency regulations are approved, dam owners willneed time before the mandated EAP submittal deadline to contract consulting engineers,prepare inundation. maps for dams and critical appurtenant structures, and prepare. EAPs.Section 6161 specifies that the department must review the inundation maps.. Upon the.department's approval of inundation maps for a dam and its critical appurtenant structures, theowners must prepare and submit their EAPs to the Governor's Office of Emergency Services(CaIOES) for approval For owners of "extremely high" hazard dams, EAPs must be submittedby January 1, 2018. Upon CaIOES's approval of the. EAP, the department must make. theinundation maps publically available.

Regulations concerning inundation maps were previously contained in CCR Title 19; however,the statutory authority was repealed by newly enacted statutes in SB 92. Government CodeSection 85$9.5 was updated to incorporate the change in regula#ory oversight of inundationmaps from CaIOES to the department. Since the department is now responsible for the reviewand approval of inundation maps, the emergency regulations that are the subject of thisrulemaking are necessary to establish authority and will be incorporated into CCR Title 23.

Given the short deadlines in the Water Code, the tack of existing authority, and the statutorilydeemed emergency, emergency regulations are. needed for the immediate preservation ofpublic safety.

Need for Proposed Reaulation to Effectuate Puraose of Statute

Water. Code Sections 6160 and 6161 require owners of state jurisdictional dams, .except thoseclassified as low hazard, to prepare and submit inundation maps and EAPs for dams and theircritical appurtenant structures, prioritizing dams by highest hazard. The proposed emergencyregulations are needed to implement, interpret, and make specific Water Code Sections 6160and 6161.

Authority and Reference

Authority citations: Water Code Sections 6078, 6160, 6161, 6162; Water Code Section. 6078;Water Code Section 723; Government Code Section 8589

Reference citations: Water Code Sections 6002, 6002.5, 6004.5, 6005, 6006, 6007, 6008, 6009,6160, 6161, 6162, 6431; Government Code Sections 8589, 8589.5; Business and ProfessionsCode Section 6700; Public Safety Code Sections 2575-2578 (repealed); FEMA 2013, FederalGuidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures(FEMA P-946}; FEMA 2Q04, Federal Guidelines for Dam Safety: Hazard Potential ClassificationSystem for Dams (FEMA 333).

Informative Digest

Summary of Existing Laws and Regulations

CaIOES previously administered the inundation map and EAP program. Regulations concerninginundation. maps were previously contained in California. Code of Regulations. (CCR) Title 19,Division 2, Chapter 2, Subchapter 4, .Sections 2575-2578.3. These regulations authorizedCaIOES,to administer the process of requiring inundation maps and. supporting technical. studiesfor all new or existing state jurisdictional dams, and described the required content and format ofthe inundation maps. and technical studies, along with. deadlines for their submittal.

The authority contained in the CCR Title 19 regulations has since been repealed by newlyenacted statutes. in Government Code Section .8589.5, which changed regulatory oversight forinundation maps from CaIOES to the department. Since the department is now responsible forthe review and. approval of inundation maps, the proposed emergency regulations that are thesubject of this rulemaking are needed #o establish authority. for incorporation into CCR Title 23.

The Federal. Emergency. Management Agency (FEMA), as part of the National Dam SafetyProgram, published federal guidelines for inundation mapping (FEMA P-946). These guidelinesare a resource for state and local governments to develop guidelines far dam safety and fordam owners to develop inundation maps.

SB 92 added Water Code Section 6161 requiring owners of extremely high hazard statejurisdictional dams to submit EAPs by January 1, 2018..Owners of high hazard statejurisdictional dams are required to subrnit EAPs by January 1, 2019. Owners of significanthazard state jurisdictional dams are required to submit. EAPs by January 1, 2021.

Policy Statement and Obiectives. The department finds that the lack of inundation maps and.emergency action plans for state jurisdictional dams .and their critical appurtenant structures,except dams classified as low hazard,. endangers public safety. The overall objective of the.proposed emergency regulations is to compile and maintain up-to-date inundation maps tosupport preparation of emergency action .plans for the subject dams and .critical. appurtenantstructures. Thespecific objective is to provide the. subject dam owners with standardsregardingthe details of preparing and submitting the required inundation maps so they can meet thestatutory deadlines.

The department has determined that the~?roaosed regulations are not inconsistent orincompatible with existingstate and federal law.

Overview. This. regulation establishes standards for the preparation of new inundation maps forcertain state-regulated dams and their associated critical appurtenant structures as required byWater Code Section 6161.

Inundation maps provide a graphical representation of the timing and extent of inundation to beexpected by the failure of a dam and its critical. appurtenant structures. Such maps must bereviewed and approved by the department as a precondition to the preparation of emergencyaction plans required by Water Code Section 6160.

The proposed. regulation .contains eleven sections within one new article. The followingdescribes the general .objectives and benefits of each section. Clarification of the rationalebehind the section is provided to aid in understanding the overall process.

Section 335. Scope of Regulations: This section establishes the scope of the regulations aslimited to the development and submittal of inundation maps and supporting technical studies.

Section .335.2 Definitions: This section. defines specific terms .used in the regulations.

Section 335.4 Hazard. Potential Classification: Water Code Section 6160 requires thedepartment classify the public safety risk of all state jurisdictional dams. Water Code Section6161 . requires the owner of a state jurisdictional dam, except a dam. classified by the departmentas a .low hazard dam, to prepare an inundation map and emergency action. plan, This sectiondescribes the four hazard classes .identified in Water Code Sections 6160 and 6167. The criteriaused for the four hazard classes are in accordance with FEMA guidelines, as .required by WaterCode Section 6160(b), with the exception that the FEMA high hazard class is subdivided intoextremely high and high hazard. Inclusion of this section is necessary to these .regulationsbecause. applicability of the regulations depends on hazard classification, pursuant to WaterCode Section 6160(a).

Section 335.6 Inundation Map Updates: This section describes circumstances under which adam owner must update an inundation map.

Section 335.8 Civil Engineering: This section ensures that inundation maps and all supportinginformation and analyses will be .prepared by a licensed civil engineer with .expertise. inhydraulics and hydrologic studies of dams.

Section 335.10 Reporting Standards: This section ensures standard units are reported for allvariables required #or display on each inundation map and supporting data. Labeling standardsare included to ensure all inundation. maps are easily understandable and clear.

Section 335.12 Technical Study: This section describes the supporting technical information,comprising. the technical study, utilized. in the preparation of an inundation map. The technical.study must be submitted along with the inundation map.

Subsection (a) ("Study Contents") describes technical and. non-technical information about thedam system that must beprovided.

Subsection (b) ("Modeling .Requirements") describes the modeling technologies to be used. Atwo-dimensional model is required in all cases unless, as specified, conditions justify the use ofa less .detailed. model .Two-dimensional modeling is becoming widely available, such as theopen source software HEGRAS recently made available from the U.S. Army Corps ofEngineers.

Subsection (c) ("Failure Scenarios") describes failure scenarios and initial conditions that mustbe employed by each model

The general assumption of a sunny-day failure is a baseline for each modeled failure scenario.An assumed sunny-day failure eliminates the need for expensive watershed and spillwaystudies and provides a reasonable upper limit estimate for warning and evacuation'. Theregulations describe conditions that are assumed in the event that astorm-induced failure orsequential dam failure simulation is modeled. Though rare for state jurisdictional dams, thecascading effect of multiple dams failing in series must be considered. The intent of thisprovision is to consider the potential. for a downstream pool to entirely or .partially absorb anupstream release. However, if the failure of an ups#ream dam leads to another dam failurefurther downstream, the inundation area for the upstream dam causing this scenario mustinclude all downstream reservoirs and floodplain reaches for which the model indicates animpact..Such considerations are important for the statutorily-required accurate characterizationof the inundation area, but may also. serve to facilitate coordinated operations befinreenneighboring dam owners during an emergency.

Section 335.14 Inundation Maps: This section. establishes the required components of eachinunda#ion map. The intent of this section is to ensure. the inundation map's efficacy during anemergency. Information capturing the time when flooding begins and recedes .must beidentified, as well as the locations of all affected critical #acilities. Likewise, the amount and.depth of flow must be provided, along with the speed of the water. These variables are standardoutputs from two-dimensional hydraulic models.. Likewise, a gridded representation of themaximum inundation depths at all locations is a standard output from two-dimensional modelsand can be displayed graphically using colors rather than labeled callouts at discrete locations.Such a grid may require post-:processing work to develop for some one-dimensional modeledoutputs.

Notwithstanding the importance of standardizatpn, the.. provision allowing.. for the additionalreporting of inundation elevations to a local benchmark is included. The. intent is toaccommodate the use of a )ocal, well-known landmark that is commonly referred to in the localcommunity and emergency management. agencies and where its use would enhance theefficacy of the inundation map.

The requirement of utilizing suitable aerial imagery is intended to aid emergency responders inquickly understanding the land use and locations of downstream development

The .provision. requiring a disclaimer statement addressing the. approximate nature of theinundation map is intended to ensure that users of the map do not regard its contents as truth.That is, the inundation area delineated by themodeled failure scenario and other variablesreported on the. map. offer one possible scenario..Each unique scenario is merely a simulationand is approximate. Limitations of the model and input data may result in inaccuracies.Evacuation areas should be planned with an understanding that each inundation map isinherently approximate.

NDSRBB (National Dam Safety Review Board EmergencyAction Plan Workgroup}. 2009. SimplifiedInundation Maps for Emergency Action Plans.

Section 335.16 Submission of Inundation Maps and Technical Study: This subsection describesthe format in which inundation maps and supporting studies are to be submitted.

Section. 335.18 Department Review and Approval: This section describes the manner in whichthe department will evaluate the submitted inundation maps and technical study for each damsystem, if the submittal is deemed .incomplete, the owner may remedy any deficiencies within aspecified timeframe.

Subsection. (b) explains that the. department will review maps. prepared on or before January 1,2018 for consistency with FEMA Guidelines.

Section 335..20 Public Availability. of Inundation Maps: This section specifies that the departmentwill post copies. of approved inundation maps to the department's website, pursuant to WaterCode Section 6161(c)(1).

Mandate on Local Agencies or School Districts

The department has determined that, .because a violation of the statute relating to an EAP or thewillful neglect to obey any order or regulation relating to an EAP would be a crime, the proposedregulations impose a mandate. on local agencies. No reimbursement. is required pursuant toSection. 6 of Article XI I IB of the. CaGfarnia .Constitution. because the only: casts that may beincurred by a local agency will be incurred because the statute. being implemented by theproposed regulations creates a .new crime or infraction within the meaning of Government CodeSection 17556.

The: department has determined .that the .proposed .regulations da not. impose a mandate onschool districts.

Economic and Fiscal Impact Estimates

The deparkment has. determined #hat the proposed emergency regulations may incur combinedeconomic. and fiscal costs exceeding $50 million .and constitute a major regulation. AStandardized Regulatory Impact Assessment will be completed during the regular rulemakingprocess.

Privafe Businesses and Individuals: The department has determined that the proposedregulations will involve additional costs and savings. #o private businesses and individuals.Private businesses and individuals own a total of 382 dams that will be subject to the proposedregulations and will incur costs to develop inundation maps. In addition, utility rate-payers mayincur costs. if public utilities that own dams subject to the proposed. regulations pass along theircosts. Private dam owners and the. public. will potentially incur savings from being better-prepared to respond to dam-related emergencies. There will be an increased demand forengineering businesses.

State Aaencies: The department has determined that the proposed regulations will involveadditional costs and savings to state agencies. The department and CaIOES will incur-costs toreview and approve inundation maps and EAPs, respectively. In addition, various state

agencies own a total of 35 dams that will be subject to the proposed regulations and will incurcosts to develop inundation maps. The state. will potentially incur savings from .being betterprepared to respond to dam-related emergencies.

focal Aaencies: The deparkment has determined #hat the proposed regulations will involveadditional costs and savings to local agencies. Local agencies, including public utilities, own atotal of 528 dams that will be subject to the proposed regulations and will incur costs to developinundation maps.-Local agencies,. including emergency management agencies and those thatown dams, will potentially. incur savings from being better-prepared to .respond to dam-relatedemergencies.

Reimbursable Cost to Local Agencies or School Districts: The department has determined. thatthe proposed regulations will not result in any additional cost. or savings to any. local agency orschool district that. is required to be reimbursed. under part 7 {commencing with Section 17500)of division 4 of the. Government Code. Na reimbursement is .required ,pursuant to .Section. 6 ofArticle XIIIB of tMe California Constitution because the only costs that. may be incurred. by a localagency wiA be incurred because the statute being implemented. by the proposed regulationscreates a new crime or infraction within the meaning of Government CodeSection 17556.

Cost or Savings in Federal Funding to the State: The department has determined that there maybe cost or savings in federal funding to the state as a result of the proposed regulations.

stateofcaiifornia · pdf fileproposed emergency regulations —inundation maps note all...

Documents