Office of the State Engineer
Basis and Purpose
for
Rules and Regulations for Dam Safety and Dam Construction
Adopted November 2, 2006

This Statement of Basis and Purpose has been prepared to elaborate upon and clarify the provisions incorporated into existing dam safety and construction Rules to include technical updating, consistency with national dam safety and engineering standards, and clarification of technical requirements for the determination of design standards. A significant change in the rules consisted of clarifying the use of modern meteorological technology in the determination of extreme precipitation applicable to determination of inflow design floods. 

RULE 1	TITLE

These Rules have been referenced by Rules and Regulations for Dam Safety and Dam Construction. The short title is Dam Safety Rules or Rules.

RULE 2	AUTHORITY

This Rule cites the statutory authority of the State Engineer to promulgate and revise these Rules.

RULE 3	SCOPE and PURPOSE

This Rule specifically identifies the activities to which these Rules apply and cites the exemptions from the Rules.  The overarching purpose of these rules is for the State Engineer to comply with the statutory requirements associated with dam design, construction, and performance resulting in providing for the public safety and reasonably reduce the potential for the loss of life as a result of dam failure. Provide for the evaluation of the performance of existing dams.  

RULE 4	DEFINITIONS

Section 37-87-102, 37-87-122, and 35-49-103, C.R.S. shall have the identical meanings when used in these Rules.  This Rule also defines additional terms used in the Colorado Revised Statutes, the engineering and construction industry, national dam safety agencies, and dam design, construction, maintenance and regulation to ensure that their meanings and usage are clearly understood. The purpose is to clarify and explain the meaning of terms where they are not self-explanatory, technical, administrative, or legal or not commonly used.

RULE 5	REQUIREMENTS FOR CONSTRUCTION OR ENLARGEMENT OF JURISDICTIONAL SIZE DAMS OR RESERVOIRS

The basis for Rule 5, "Requirements for Construction or Enlargement of Jurisdictional Size Dams or Reservoirs," is Section 37-87-105, C.R.S., which states that plans and specifications for a dam must be approved by the State Engineer according to regulations established by the State Engineer.  To provide reasonable technical requirements that will protect the safety of the public from failure of dams. The purpose of this rule is to provide administrative procedures and technical requirements for the design and determine the adequacy of the design for approval of the construction or enlargement of a dam or reservoir.  The provisions of Rule 5 establish the necessary elements of an application package to ensure adequate information concerning a project is presented for comparison against engineering standards, and to ensure a standardized, durable public record is filed. To provide a standard consistent with the industry for construction drawings/plans to guide construction work and provide a permanent record for the file, and to update the dams database. 

Rule 5.1  The basis of this rule is Section 37-87-105, C.R.S.  The purpose is the need of the State Engineer to have a summary of information concerning the engineer, owner, and structure which is available for public inquiries, while the remaining project documents are held confidential until approved, to provide a permanent record for the file, and to update the dams database.

Rule 5.2  The basis for this rule is Section 37-87-105, C.R.S. and the standard of the industry in that construction drawings/plans are a part of the basic documents used to guide construction work.  The purpose of this rule is to provide guidelines and standards for the preparation of plans.

Rule 5.2.1  The purpose of this rule is that plans must be complete in sufficient detail to ensure the contractor will understand exactly how the dam is to be built. Additionally, the plans will enable the State Engineer to determine how the dam will be constructed from which a determination may be made concerning the adequacy of the design.

Rule 5.2.2  The purpose of this rule is to provide information on the plans for maintaining the State Engineer's filing system and dams data base.  The seal is required by the "Bylaws and Rules of the Board of Licensure Registration for Professional Engineers and Professional Land Surveyors".  The AS-CONSTRUCTED statement is necessary for the final filing of the record for future use.

Rule 5.2.3  Section 37-87-105, C.R.S. requires plans to be filed with the State Engineer. The filing of plans, which has been required since 1925, has served as a valuable resource for the State Engineer to determine the safe storage in existing dams, and as planning information for consulting engineers evaluating the enlargement, modification, or repair of a dam. The purpose of requiring the drawing size of 24 x 36 inches (or 22 x 34) is to maintain the current filing system. The purpose for requiring high quality drawings is to provide archival quality records which will be available for future use.

Rule 5.2.4  This rule provides a uniform space on each drawing for reproduction, and room to bind the drawings in the archive books.

Rules 5.2.5  This rule allows for microfilming and producing legible scaled drawings for the general public use.
	
Rule 5.2.6  This rule provides for a space to affix a file number unique to the plans for convenient filing and retrieval.  

Rule 5.2.7  This rule is self-explanatory and allows a user to ensure a set of plans is complete.

Rules 5.2.8  This rule allows for microfilming and producing legible scaled drawings for the general public use.

Rule 5.2.9  This rule requires physical characteristics of the dam and reservoir to be presented in a succinct format.

Rule 5.3  The basis for this rule is Section 37-87-105, C.R.S. and the standard in the dam building industry in that construction specifications are a part of the basic construction documents which define the minimum requirements of quality of material, and workmanship of the construction. The purpose of this rule is to provide guidelines and standards for the preparation of specifications.

Rule 5.3.1  The purpose of this rule is to establish the requirements to properly title the front or cover sheet of the specifications; to provide standards for the engineer's seal as required by the "Bylaws and Rules of the Board of Licensure Registration for Professional Engineers and Professional Land Surveyors” to provide the form of the State Engineer's approval statement; and to provide the form of the engineer's certificate of AS-CONSTRUCTED specifications.

Rule 5.3.2  The purpose of this rule is to allow easy location of the various parts of the specifications.

Rule 5.3.3  This rule provides for a durable record of the construction specifications for immediate and future use, and to maintain the State Engineer's filing system.

Rule 5.3.4  This rule is consistent with Section 37-87-105, C.R.S., which requires approval of plans and specifications by the State Engineer. The purpose is to provide notice to the contractor that material changes require prior written approval of the State Engineer.

Rule 5.3.5  This rule complies with Section 37-87-105, C.R.S.

Rule 5.3.6  The basis for this rule is the standard in the industry.  Adequate plans and specifications define the process and materials required to build a dam.  In order to assure the dam is properly built, there must be adequate monitoring by an experienced engineer.  This requirement is the same as the quality of control applied to construction of highways, large buildings, and structures throughout the industry.

Rule 5.3.7  The purpose of this rule, with its subsections, is to outline in general terms the basic elements of a set of specifications.  

Rule 5.4  The State Engineer uses the classification of a dam as a means to set priorities and allocate resources in the administration of the dam safety program. Because the design requirements and standards in these Rules and Regulations are based upon the classification, the engineer cannot begin the design work until a classification is determined.  A classification report provides the justification for determining the applicable design standards.  In the case of a High Hazard dam, which requires the highest standards, a classification report is not necessary.

Rule 5.4.1  The purpose of this rule is to ensure that the engineer has properly determined the effects of the dam's failure on downstream property and life and has assigned the appropriate classification. Also, it describes the need for sufficient and conclusive evidence that the dam is properly classified for the purpose of substantiating the use of lesser design standards than that required of a High Hazard dam.

Rule 5.4.1.1  The purpose of this rule is to provide for a means to interpolate flooding conditions between cross sections, and provide a visual indication of the flood inundation impact on properties.  The flood plain map in conjunction with the graphic representation of manmade features is the primary source of a classification.

Rule 5.4.1.2  The purpose of this rule is to provide a scaled graphic representation of the selected cross sections of the flood channel which is used for computing the stage discharge relationships.  These cross sections along with the average velocity determined from the stage discharge relationship provide an indication of the potential destructive force of water which is also used in determination of a classification.

Rule 5.4.1.3  The purpose of these rules is to enable the State Engineer to check the reasonableness of the programs and parameters used.  Because the estimation of stream flow and dam break parameters such as Manning's "n” values and the "time to breach" values are subjective, the sensitivity of these values to the calculated results is necessary to assure the correctness of the results.

Rule 5.4.2  The basis for this rule is Section 37-87-105, C.R.S.. The hydrology report contains the necessary information upon which the adequacy of a proposed spillway is determined.  In addition, each hydrology study is site specific; i.e., the determination of the inflow design flood is based upon the drainage basin size, elevation, topography, geology, and vegetative cover as well as on precipitation and moisture conditions of the basin as discussed below.

Rule 5.4.2.1  This rule is to assure the State engineer has the information necessary to review and evaluate the adequacy of the hydrology applicable to the dam the specifics of the requirements are described in each subsection below:

Rule 5.4.2.1.1  The purposes of this rule are to show the location of the dam on a topographic map for checking the boundaries of the drainage basin; to present information necessary for supporting the calculations of the inflow design flood; to provide the name of the stream for evaluating (in part) the impact of the structure on existing water rights; and to provide the elevation of the dam crest which is an important parameter used in the determination of the magnitude of precipitable moisture available to produce the design rainfall for determining the inflow design flood.

Rule 5.4.2.1.2  The purpose for this information is its use to determine the amount of rainfall which is extracted from the event resulting in the determination of the excess rainfall available for runoff.

Rule 5.4.2.1.3  The purpose of this rule is to check the parameters derived from the basin characteristics and precipitation upon which the inflow design flood is calculated. It serves as input data for the independent review and check of the inflow design flood and its appropriateness to the classification of the dam.

Rule 5.4.2.1.4  The purpose of this rule is to check if the spillway rating table is determined from the appropriate equations for the type of spillway designed.  Using the spillway equation, a computer run is made to check if the spillway is large enough to pass the inflow design flood without overtopping the dam.

Rule 5.4.2.1.5  The purpose of this rule is to provide reservoir storage data to evaluate the effect of storage during the routing of the inflow design flood. 

Rule 5.4.3  The basis for this rule is Section 37-87-105, C.R.S. and the standards in the industry.  The purpose is to define the scope required for presenting support for the geotechnical design of a dam.  As the consequences of a dam failure become more significant, greater care is required in the investigation and design for High Hazard and Significant Hazard dams.

Rule 5.4.3.1  The basis for this rule is the standards in the industry which may be found in manuals developed by the U.S. Bureau of Reclamation and the U.S. Army Corps of Engineers and several text books prepared by consultants and university professors.  The purpose is to provide sufficient information on the character of the foundation and geological aspects of the dam in order to evaluate the design of the dam.  Because loss of life can occur due to the failure of a High Hazard dam, and significant damage can occur from Large Significant Hazard dams, the threat posed by earthquakes must be evaluated in the design.

Rule 5.4.3.2  The basis for this rule are the standards in the industry and its purpose is to outline in general terms the types and extent of the geotechnical investigation of the foundation and materials used in construction of the dam.  Because of the potential for loss of life and significant damage due to the failure of High and Significant Hazard dams, the prescribed requirements are necessary to assure the safe design of the dam.  Specifically, a foundation investigation is needed to determine if it can support the load imposed by the dam, whether seepage will transport materials leaving a void and causing a subsequent collapse, and whether seepage will preclude the dam from retaining water in storage.  The purpose is to assure the dam is safe, feasible, and appropriate for the site conditions.

Rule 5.4.3.3  The purpose of this rule and its subsections is to assure the dam owner and the State Engineer that there are sufficient materials available to construct the dam as designed. The qualitative tests listed in the subsections are the minimum necessary to determine the properties of the materials to ensure the dam will perform safely, and to ensure inadequate soils are discovered so that they can be compensated for in the design.

Rule 5.4.3.4  The purpose of this rule is to provide the geotechnical investigation requirements of Rule 5.4.3.3 for Low Hazard dams to a level which comports with the risks involved for this class of dam.

Rule 5.4.3.5  The purpose of this rule is to provide the requirements which are commensurate with consequences of failure of the determined size and hazard class of dam, but providing sufficient information to evaluate the design.

Rule 5.4.3.6  The purpose of this rule and its subsections is to provide the requirements for the minimum level of investigation of a spillway channel located on an earth foundation.  Colorado has many dams which have spillways located on earth foundations.  Some have successfully withstood floods, many have failed slowly with time, and others have failed quite rapidly.  Therefore, the design engineer must investigate the spillway channel and develop his design accordingly.  Some dams are exempt because the consequences of the failure.

Rule 5.4.3.7  The purpose of this rule is to ensure the engineer has evaluated the ability of the spillway channel to withstand the erosion caused by the flow of water with time.  Some dams are exempt because the consequences of the failure.

Rule 5.4.4 and 5.4.5  The basis of this rule and subsections is Section 37-87-105, C.R.S.. The information included in the Design Report provides the necessary support for the conclusions reached and presented in the plans and specifications.  The presentation of the engineering calculations and assumptions used in the design will expedite the review process and will reduce the number of questions concerning the design.

Rule 5.5  The basis for this rule is Section 37-87-107, C.R.S.. The purpose of this rule is to provide an appropriate level of monitoring the structural and operational performance of a dam to respond to potential failure conditions before they become so advanced as to fail the structure and potentially result in the loss of life. The specific aspects of each rule are provided below.

Rules 5.5.1 & 5.5.2  The purpose of these rules is to facilitate accurate monitoring of the dam's performance and enforcement of restriction orders.  In addition, gage rods are used in the administration water rights.

Rule 5.5.3  The purpose of this rule is to provide monitoring of High and Significant Hazard dams in order to identify emerging problems.  Early detection of developing problems can allow the owner to take emergency action before the dam fails.

Rule 5.5.3.1  The purpose of this rule is to detect movement of the dam early enough for the owner to take emergency action before the dam fails.

Rule 5.5.3.2  The purpose of this rule is to provide for the monitoring of seepage from a dam.  These values, in conjunction with the water storage level, establish a performance history.  The resulting trends can detect changes in the seepage.  In the case of reduction in flow, the drains could be beginning to clog and can cause an increase in the saturation level within the dam and a resulting instability of the embankment.  If the drain water flow increases, there may be a piping problem developing.

Rule 5.5.3.3  The purpose of this rule is to provide a means to record the location of problems found on a dam during an inspection.

Rules 5.5.3.4, 5.5.3.5 & 5.5.3.6  The purpose of these rules is to monitor the saturation level within the dam.  The stability of the dam is affected by the location of the saturation level within the dam.  These saturation levels in conjunction with the seepage monitoring provide an early warning of pending dam safety problems.

Rule 5.5.4  The basis for this rule is Section 37-87-107, C.R.S.. The purpose for the subsections of this rule is identical to Rule 5.5.3. The requirements of this rule are commensurate with the consequences of the failure of a Low Hazard dam.

Rule 5.5.5  The purpose of this rule is to state that accurate monitoring of the dam's performance is not required for NPH dams, except as used in the administration water rights (see Rule 5.5.2).

Rule 5.6  The basis for this rule is Section 37-80-110(1)(e), C.R.S.  The purpose of this rule is to assure the basis of the fee is correct and to compile a record of costs of construction for use by the State Engineer to answer inquiries from other state agencies and the legislature.

Rule 5.7  The basis for this rule is also Section 37-8-110(1)(e), C.R.S..  The rule comports with the statute.  The purpose of this rule is to provide this fee requirement within these rules for proper notification to a dam owner.

Rule 5.8  The basis for this rule and its subparts is Section 37-87-105, C.R.S.. The purpose for these rules is to deal with technical obsolescence and to ensure the structure will meet current standards.  For example, the hydrologic criteria or classification may have changed during the interim period.

Rule 5.9  The basis for this rule is Section 37-87-105, C.R.S., and applicable industry dam construction and dam safety standards.  The purpose of this rule is to establish minimum standards for reasonable flood protection of dams and reducing the failure of dams by overtopping.  This rule parallels national standards; has criteria which is based upon the consequences of a failure such as loss of life, significant property damage, and protection of the dam structure and provides a reasonable level of safety. Four procedures, each providing the applicable public safety to the appropriate dam conditions are available to the owner and engineer in analyzing and evaluating inflow design flood characteristics. Several tables provide easy reference and comparison of acceptable engineering procedures. 

Rule 5.9.1.1 & 5.9.1.2  The purpose of these rules is to protect against the failure of a dam and reduce the potential for the loss of life due to dam failures as a result of an extreme hydro-meteorological event.  The application of reasonable standards for the reduction of the potential for the loss of human life is intended by the public, legislature and industry.  If loss of life is expected by failure of a new high hazard dam, the highest standards must be applicable. 

Rule 5.9.1.3  The purpose of this rule is to provide a modern meteorological method for the determination of the appropriate Extreme Storm Precipitation  including the depth–duration of the design extreme storm appropriate for the determination of the inflow design flood. Specific application of the results of the Extreme Storm Analysis Tool (EPAT) is described in the subsections below. The development of the EPAT is a state of the art tool that solves the 16 year hold on spillway capacity of dams above 7500 ft elevation. 

Rule 5.9.1.3.1  The purpose of this rule is to specify the requirements for the specified dams to reduce the potential for the loss of life from the failure of a dam due to overtopping from extreme hydrologic events.  

Rule 5.9.1.3.2  The purpose of this rule is to specify the requirements for the specified dams to reduce the potential for significant property damage from the failure of a dam due to overtopping from extreme hydrologic events.  

Rule 5.9.1.3.3  The purpose of this rule is to specify the requirements for the specified dams to reduce the potential for significant property damage from the failure of a dam due to overtopping from extreme hydrologic events.  

Rule 5.9.1.3.4  The purpose of this rule is to specify the requirements for the specified dams to reduce the potential for property damage from the failure of a dam due to overtopping from extreme hydrologic events.  This rule matches the 100-year floodplain requirements applied by regulatory agencies and Section 37-87-102, C.R.S.  

Rule 5.9.1.3.5  The purpose of this rule is to protect against small damage while recognizing the relative amount of damage minor-sized Low Hazard dams and large NPH dams could cause, and balancing this against the risk of a 50-year flood being exceeded in the life of the dam.  

Rule 5.9.1.3.6  The purpose of this rule is to provide a spillway which will reduce the loss of the dam and its socio-economic impact to an acceptable level.

Rule 5.9.1.3.7  The purpose of this rule is the same as Rule 5.9.1.3.4 while recognizing the relative lesser impact of the failure and loss of these size structures. Another purpose is to protect against loss of the dam.  It is based upon the same standards provided above, in that it provides a minimum level of protection for the dam. In addition, the failure of dams must be minimized in order to provide protection to the social and economic factors associated with the loss of the dam.

Rule 5.9.1.4  The purpose of this rule is to allow PMP estimates to be determined from the National Weather Service, Hydrometeorological Report Series. The IDF requirements for determining the spillway capacity using the appropriate HMR are summarized in Table 5.2. The purpose of this rule is to specify the requirements for the specified dams to reduce the potential for the loss of life or property damage from the failure of a dam due to overtopping from extreme hydrologic events. The bases for Rule 5.9.1.4.1 through 5.9.1.4.8 are parallel to the basis for rule 5.9.1.3.1 through 5.9.1.3.7.  
 
Rule 5.9.1.5  The purpose of this rule is to provide adjustments of the PMP determined from the HMR for dams constructed at elevations over 5,000 feet.

Rule 5.9.1.6  The purpose of this rule is to allow a site specific determination of probable maximum precipitation for individual dams located in a specific drainage basin. The purpose of this rule is to specify the requirements for the specified dams to reduce the potential for the loss of life or property damage from the failure of a dam due to overtopping from a site specific probable maximum precipitation event using approved meteorological techniques.

Rule 5.9.1.7  The purpose of this rule is to recognize that overtopping dam failures may be insignificant.  It is based upon the premise that if all downstream flood damage would occur due to the base flow flood, it is not logical to require additional spillway protection for the downstream area.  Another purpose of this rule is to outline the criteria against which a study is compared and to establish the minimum documentation requirements to justify the use of an incremental damage analysis for a spillway design. The base flow flood is based upon no dam discharge in accordance with Section 37-87-104(2), C.R.S.

Rule 5.9.1.7.1  The purpose of this rule is to establish an incremental depth and a velocity limit which is not expected to cause loss of life or significant property damage. The basis is a combination of the standards in the industry, which includes research by the Federal Emergency Management Administration (FEMA) and the Stanford Risk Analysis Studies that indicates loss of life is not expected if the depth of water is two feet or less, and that a review of typical Federal Insurance Administration (FIA) flood damage curves shows the incremental damage for each two feet of depth, will range from two (2) percent of the structure value near the deepest portion of the flood plain to about thirteen (13) percent along the edges of the floodplain.  Additionally, in the dam-break impact zone, relatively inexperienced adults can safely wade in water and structures are not expected to wash away or fail, if the mathematical product of the incremental depth times velocity is less than seven (7).  The intent is to balance the costs of a larger spillway and the expected additional damages caused by the overtopping dam failure.  It should be noted that the effect of plus or minus ten (10) percent of the flood magnitudes is not expected to make a significant difference in the incremental depths.

Rule 5.9.1.7.2  The basis for this rule is Section 37-87-105, C.R.S.. The purpose of this rule is to define the necessary evaluations and documentation to support the conclusions that an incremental damage study is complete and appropriate.  In some cases where the downstream channel is complex and difficult to evaluate, the State Engineer may require additional documentation and detail, especially in the case of High Hazard and Significant Hazard dams.

Rule 5.9.1.8 & 5.9.1.9  The basis of these rules is Section 37-87-105, C.R.S. It agrees with the standards of the dam building industry.  The purpose of this rule is to assure safe design of earth dams.

Rule 5.9.1.10  The purpose of this rule is to allow continued use of spillways designed to meet prior standards which are considered to meet reasonable public safety criteria.

Rule 5.9.2  The seismic criteria listed below are the standards in the industry and the basis is Section 37-87-105, C.R.S.  The purpose of each is identified below.

Rule 5.9.2.1  Dams classified as High or Significant hazard are required to be analyzed for seismic stability consistent with industry engineering standards and applicable risk standards.  Seismic analysis for water storage dams is required to identify appropriate parameters for design decisions that reduce the potential failure and potential loss of life and property damage. The review by the State Engineer of the appropriate data sheets, calculation sheets and computer program output computations and analysis are necessary for the determination of reasonable design and construction. 

Rule 5.9.2.1.1  The purpose of this rule and Rules 5.9.2.1.1.1 through 5.9.2.1.1.3 is to specify the appropriate seismic parameters and minimum standards to be used for design to protect human life and property.  The seismic parameters shall be based on the design earthquake and seismic events used as industry standards and described in these subsections.

Rule 5.9.2.2  This purpose of this rule is to comport with the standard of the industry for the analysis of materials in the foundation, reservoir area and proposed embankment shall be completed to determine the potential for liquefaction, earthquake-induced sliding, or other seismic sensitivity.  The analysis is necessary to identify design requirements to provide a minimum level of protection for High Hazard and Significant Hazard dams which have the potential for loss of life and significant property damage. 

Rule 5.9.2.3   The purpose of this rule and Rules 5.9.2.3.1 through 5.9.2.3.3 is to specify the appropriate industry pseudostatic analysis standards for embankment dams to be used for design to protect human life and property. 

Rule 5.9.2.4  This rule provides the required seismic design standards for concrete dams consistent with the dam design and construction industry. 

Rule 5.9.2.5  The purpose of this rule is to provide an alternative analysis technique to situations for which it has been found to be appropriate, and to require a more realistic analysis of the effects of seismic shaking for those dams subjected to relatively severe ground motions.  The requirement for a minimum of three feet of freeboard remaining following deformation of the dam is intended to ensure that sufficient dam structure remains following the design earthquake to prevent subsequent uncontrolled loss of the reservoir by overtopping.

Rule 5.9.2.6  The rule specifies that a seismic analysis must address critical appurtenant structures which the failure of such structures may result in the potential failure of the dam.  

Rule 5.9.3  The basis of this rule and Rules 5.9.3.1 through 5.9.3.10 is to specify the appropriate industry geotechnical and foundation investigation and analysis standards. The purpose is to ensure that a thorough investigation of the geotechnical aspects of the dam site has been performed and to provide a minimum level of protection for dams which have the potential for loss of life and significant property damage.

Rule 5.9.4  This rule and Rules 5.9.4.1 through 5.9.4.3.6.2 identify requirements for the design and construction of embankment dams. The requirements are consistent with dam design and construction industry standards.  These rules provide specific requirements and standards for factors of safety, seepage and drainage, dam geometrics, material compaction, slope protection and geosynthetics.

Rule 5.9.4.1 This rule and Rules 5.9.4.1.1 through 5.9.4.1.3 provide the detailed evaluation and procedures required for slope stability analysis including acceptable factors of safety, appropriate cross-sections and applicable loading conditions. The requirements are consistent with dam design and construction industry standards for the reasonable reduction in potential dam failure which could result in the loss of life and property damage. 

Rule 5.9.4.2  This rule and Rules 5.9.4.2.1 through 5.9.4.2.3 provide the detailed evaluation and procedures required for seepage and internal drainage analysis and  design including the testing and parameters, material considerations, and material compatibility. The requirements are consistent with dam design and construction industry standards for the reasonable reduction in potential dam failure which could result in the loss of life and property damage. 

Rule 5.9.4.3  This rule and Rules 5.9.4.3.1.1 through 5.9.4.3.1.11 provide requirements for the dam design report and minimum standards for the physical configuration of the dam. These requirements are consistent with dam design and construction industry standards.  

Rule 5.9.4.3.2  This rule and Rules 5.9.4.3.2.1 and 5.9.4.3.2.2 provide the requirements and standards for material compaction consistent with dam construction and design standards.

Rule 5.9.4.3.3 This rule defines the requirements and standards for rock riprap used for erosion protection consistent with dam construction and design standards.  This rule requires filters and drains to be designed and constructed consistent with Rule 5.9.4.2.

Rule 5.9.4.3.5  This rule provides the necessary requirements for the design and construction of internal drains such that they are designed, constructed, and perform in a manner that are consistent with industry standards and reduce the potential for dam failure. 
 
Rule 5.9.4.3.6  This rule and Rules 5.9.4.3.6.1 and 5.9.4.3.6.2 identify the acceptable use and design of geosynthetics. 

Rule 5.9.5 This rule and Rules 5.9.5.1 through 5.9.5.6.5 identify requirements for the design documentation and design and construction standards of concrete dams. The requirements are consistent with dam design and construction industry standards.  These rules provide specific requirements and standards for arch dams, gravity dams, and roller compacted concrete dams including the acceptable factors of safety, seepage and drainage, structural stability, hydrostatic pressure, loading conditions, dam geometrics, slope and overtopping protection. The requirements are consistent with dam design and construction industry standards for the reasonable reduction in potential dam failure which could result in the loss of life and property damage.

Rule 5.9.6  This rule and Rules 5.9.6.1 through 5.9.6.2.5 provide the documentation required, design criteria and types of acceptable spillway and outlet configurations consistent with dam design and construction industry standards for the reasonable reduction in potential dam failure which could result in the loss of life and property damage. 

Rule 5.10  This rule and Rules 5.10.1 through 5.10.1.7 provide the necessary reservoir site preparation, ownership and easement requirements, access for emergency response and maintenance, and utility construction standards for the reasonable reduction in potential dam failure which could result in the loss of life and property damage. 

Rule 5.10.2  This rule and Rule 5.10.2.1 through 5.10.2.5.4 provide the necessary requirements for river and water diversion during construction including the estimation of flow, documentation of the diversion plan, and the supporting engineering required to support the proposed water diversion plan. The requirements are consistent with industry standards to provide a reasonable reduction in potential loss of life and property damage. 

Rule 6 	REQUIREMENTS FOR ALTERATION, MODIFICATION, OR REPAIR OF AN EXISTING DAM

Rule 6 and 6.1.1  The basis for this rule is Section 37-87-105, C.R.S.. The purpose is to outline the requirements for an owner proposing to alter, modify, or repair an existing dam, and to establish the design, construction, evaluation, analysis and engineering requirements for such modifications to existing dams.

Rule 6.1.2  The purpose for this rule is to expedite the review process for repair of existing dams, and alteration to nonjurisdictional size, by modifying the administrative procedures for filing until completion of the work.  Generally these types of plans are simple, require minimal detail, and the quality of the work can be maintained adequately through a simplified procedure, while meeting the requirements of public safety.  

Rule 6.1.2.1  The purpose of this rule is to provide a summary of information concerning the work for the permanent record, and to update the dams database.  The purpose for requiring an engineer to prepare the plans is for the protection of the public's safety.  The purpose for requiring that plans and specifications be submitted is for the State Engineer to ascertain that the plans and specifications will provide the quality control necessary to assure a safe dam.

Rule 6.1.2.2  The purpose of this rule is to enable the State Engineer to determine if the plans will provide the detail necessary to assure the construction or alteration of a safe dam.  The plans must also serve as contract documents for bidding and execution of the work, between the owner and the contractor.

Rule 6.1.2.3  The purpose of this rule is to provide a public record of the dam, which will maintain the current filing system with archival quality plans for future use.  Records are not required to be filed for nonjurisdictional dams.  The referenced rules are necessary by law to collect the filing fees to assure adequate control is maintained during construction in accordance with the approved plan, and to assure a record of construction acceptance and providing a record of the construction are maintained for future use.  Because it is intended to enable the construction of the work as soon as possible after approval, the time limits are not applicable.

Rule 6.1.2.4  The purpose of this rule is to permit exemption from the provisions above for a dam which is not expected to constitute a hazard when being altered from a jurisdictional dam to a non-jurisdictional dam.

Rule 6.1.3 and Rules 6.1.3.1 through 6.1.3.4  The basis of Rules 6.1.3 and 6.1.3.1 through 6.1.3.4 is Section 37-87-105, C.R.S. which states that plans and specifications for the repair of a dam must first be approved by the State Engineer if such repair would affect the safety of the dam.  The purpose of Rule 6.1.3 and 6.1.3.1 through 6.1.3.4 is to provide the application and filing requirements for repairs to dams which are of smaller size and of less risk to the loss of life and property damage due to failure.  The State Engineer will retain his regulatory authority and oversight responsibility, but the majority of the work will be done directly by, or under control of, the owner.  The State Engineer will provide technical advice and require quality control by the owner.

Rule 6.1.4  The basis for this rule and its subparts is Section 37-87-105, C.R.S. and the reasonable industry standards for the reduction of the potential for the loss of life and property damage due to the failure of a dam from the overtopping of the dam as a result of an extreme hydrological event.  The purpose of this rule is to establish minimum standards for flood protection of reservoir dams with the objective of minimizing the loss of dams by overtopping that are requisite to their hazard class.  

Rule 6.1.5  The basis of this rule is Section 37-87-105, C.R.S. It agrees with the standards of the dam design and construction industry and reasonable public safety.  The purpose of this rule is to assure safe design of earth dams.

Rule 6.2 and 6.3  These rules provide limitations for the timely resolution of design review comments and the timely dam construction and completion of dams after approval of plans and specifications. The time limitations are necessary to assure the dam design and construction plans approved are consistent with current industry design and construction standards. 

Rule 7 	REQUIREMENTS FOR REMOVING OR BREACHING AN EXISTING DAM

Rule 7  The basis for this rule is Section 37-87-105, C.R.S. because a breach is considered an alteration to a dam.  The purpose is to assure the safe removal of a dam, and that the dam, as breached, will not be a threat to public safety.

Rule 7.1.1  The purpose of this rule is the same as Rule 5.1.

Rule 7.1.2  The purpose for requiring an engineer to design the breach of a High Hazard and Significant Hazard dam is that the breach requires compliance with industry standards and the structures must determined that they no longer are a threat to the public safety.

Rule 7.1.2.1  The required physical configuration is necessary to prevent the effects of stored water and the potential widening of the breach which could cause potential downstream damage.  The 100-year flood was chosen because it provides a reasonable level of protection.  This also agrees with the principles of floodplain management.

Rule 7.1.2.2  The purpose of this rule is to prevent the breach from closing due to a slope failure.  The minimum slope requirements are to reduce the chance of the slope from sloughing during a flood.

Rule 7.1.2.3  The purpose of this rule is to mitigate the potential damage downstream due to transport of the accumulated silt during flooding.

Rule 7.1.2.4  The purpose of this rule is to require careful breaching of the dam storing water because breaching is a dangerous activity which, if uncontrolled, could cause loss of life and property damage.

Rule 7.1.2.5  The purpose of requiring plans is to enable the State Engineer to review the plans to assure that they comply with these rules and they also serve as contract documents for the contractor's forces.

Rule 7.1.2.6  The purpose of being under the purview of an engineer is to assure that the breach is done per the plans described in Rule 7.1.2.5.

Rule 7.1.2.7  The purpose of this rule is to provide certified documentation to the State Engineer that the dam has been breached in accordance with the approved breach plan.

Rules 7.1.3 and 7.1.3.1 through 7.1.3.4  The basis for these rules is Section 37-87-105, C.R.S.. The purpose of the rules is to mitigate the effects of the storage of water and the potential widening of the breach due to flood flows.  Another purpose is to 
simplify the process for breaching Low Hazard and NPH dams. The minimum dimensions are established, which do not require plans prepared by an engineer, to minimize the costs associated with a breach of a Low Hazard or NPH dam because the consequences of damage are small.

Rule 8	FEES

The purpose of this rule is to provide a formula for the applicant to use to determine the required filing fee.

Rule 9	CONSTRUCTION OF JURISDICTIONAL SIZE DAMS

Rule 9.  The basis for Rule 9 "Construction of Jurisdictional Size Dams" is Section 37-87-105, C.R.S, giving the State Engineer authority to require the material used and the work of construction to be accomplished in accordance with regulations. The requirements for quality control are also based upon the size and class of the dam being commensurate with the consequences of the failure of a dam.  A balance is sought between cost to achieve safety and the risk of failure and its consequences. More stringent requirements are necessary for High Hazard dams than Significant Hazard dams and Low Hazard dams.  For even small dams, however, the loss of even one life which resulted from the failure is deemed unacceptable and requires the highest standard of care.  For damage, however, the requirements for control are reduced in accordance with the size of the structure.

Rule 9.1  The basis is Section 12-25-101, et al., C.R.S.. The purpose for requiring the owner to provide an engineer is to protect the public from the construction of hazardous dams by providing a qualified specialist to observe the construction of the dam and assure that it conforms to the approved plans and specifications.  Also, the State Engineer does not have the resource to provide this important function on a sufficient basis, but must monitor the performance of the work through checks and review of the engineer's work.

Rule 9.1.1  The basis is Section 37-87-105, C.R.S. The purpose for requiring a comprehensive construction observation plan is to assure that adequate quality control and construction observation, as well as timely inspections by the State Engineer, are provided for dams that have the potential for causing loss of life.  The 30 days is necessary in order to allow for time to review the plan and make any revisions to it before the start of construction.

Rules 9.1.1.1 through Rule 9.1.1.7  The purpose for requiring the date of the start of construction is so the State Engineer may plan for the administration and inspection of the work.  The purpose for requiring the names and qualifications of the engineer are self-evident; making sure qualified persons are being utilized for the specialized work of dam construction, and the qualifications dictating how often, and to what extent, the State Engineer will need to monitor the work.  The purpose for requiring a construction observation schedule is to ascertain that sufficient inspections will be made to assure that quality control is provided and to schedule the State Engineer's inspections.  The purpose for requiring a schedule of rock foundation observations by a geologist, or engineering geologist, is to ascertain that critical aspects of the foundation will be adequately evaluated in regard to the design.  A specialist such as a geologist is necessary for High Hazard dams because of the unique features which could affect the safety of the dam; e.g., faults, fractures (and their treatment), and competent rock.  The purpose for requiring inspections by the gate manufacturer is to ascertain that the assembly was followed correctly.  The gate manufacturer is best qualified to do this. Preassembled gates and frames at the manufacturer's plant could be waived and inspected for adequacy by the engineer.  The purpose for identifying the materials testing firm is to ascertain their qualifications and to know who to correspond with.  The purpose for requiring a schedule of tests is to ascertain that an adequate amount of testing will be conducted to assure the performance of the materials as designed (if not covered by the specifications).

Rule 9.1.2  The purpose of this rule is to prevent delays in the engineer's and contractor's accomplishment of the work.  The consequences of the unacceptable conduct of the work and quality control justifies approval of the plan before construction begins.

Rule 9.1.3  The basis is Section 37-87-105, C.R.S..  A preconstruction meeting is normally conducted between the engineer and the contractor for major projects.  The purpose of the rule is to include the State Engineer in the meeting so that he may ascertain that the work will proceed without delay and problems dealt with, to establish reporting requirements, and to assure that the public's safety will not be jeopardized by the water diversion works during flooding.  The name of the contractor and its principal employees are needed in order to know who to communicate with if the engineer is not available.  They are also needed for the record.

Rule 9.1.4  The basis is Section 37-87-105, C.R.S..  The purpose of the rule is to provide sufficient construction observation to ensure that the work corresponds to the approved plans and specifications, and to discover changed conditions which might jeopardize the safety of the dam as designed.

Rule 9.1.5  The basis is Section 37-87-105, C.R.S.  The purpose is to determine when the State Engineer should make construction inspections to evaluate the acceptance of the construction, and to provide a record which can be used to evaluate the future behavior and safe storage level of the dam.

Rule 9.1.6  The basis is Section 37-87-105, C.R.S..  The purpose of the rule is for the State Engineer to monitor the progress of the work and schedule inspections.  The purpose for the summary report is to provide a record for future safety inspections of the dam.

Rule 9.1.7  The basis is Section 37-87-105, C.R.S..  The purpose is the enable the State Engineer to plan for and inspect critical portions of the construction, which will serve to evaluate the contractor's performance, and serve as part of the basis for acceptance of the work.

Rule 9.1.8  The basis is Section 37-87-105, C.R.S..  Any significant change in the plans which could affect the safety of the dam must be approved by the State Engineer in order to maintain the validity of the original approval. The State Engineer will review the change orders promptly to not unduly delay the contractor's work

Rule 9.1.9  The basis is Section 37-87-105, C.R.S..  The purpose is to enable the State Engineer to plan for and make a final inspection of the work before preparing the written acceptance.

Rule 9.1.10  The purpose of this rule is to enable the State Engineer to respond to the completion of construction within the sixty day limit.

Rule 9.2  The basis is Section 37-87-105, C.R.S..  The purpose is the same as Rule 9.1, except the requirements have been reduced to a level commensurate with the consequences of the failure of these sizes and classes of dams. An engineer is required to provide the quality control which cannot be provided by the State Engineer.  Sufficient notifications and qualifications are required in order to enable the administration of the project by the State Engineer.  The purposes are the same as their counterparts covered in Rule 9.1, but the requirements have been reduced.

Rule 9.2.1  The purpose is the same as for the pertinent parts of Rule 9.1.1.

Rule 9.2.2  The purpose is the same as Rule 9.1.4, but the expected frequency of the inspections, which are left to the judgment of the engineer, are reduced; but are required often enough to judge the quality and maintain control of the work.

Rule 9.2.3  The purposes are the same as for Rules 9.1.5, 9.1.6 & 9.1.7.

Rule 9.2.4  The purpose is the same as for Rule 9.1.8.

Rule 9.2.5  The purpose is the same as for Rule 9.1.9.			

Rule 9.2.6  The purpose is the same as for Rule 9.1.10.

Rule 10	ACCEPTANCE OF CONSTRUCTION OF JURISDICTIONAL SIZE DAMS

Rule 10  The basis for Rule 10, "Acceptance of Construction of Jurisdictional Size Dams is Section 37-87-105, C.R.S., which states that no work shall be deemed complete until the State Engineer furnishes to the owner a written acceptance of the work.

Rule 10.1  The purpose for approval is to maximize the beneficial use of water by allowing storage if a project is substantially complete in the judgment of the State Engineer and the engineer has complied with Rule 10.2.  Some approvals may also require contingencies for full storage or even partial storage (e.g., controlled filling, monitoring, completion by a certain date) to assure the safety of the dam.

Rule 10.2  The basis is Section 37-87-105, C.R.S.. The purpose is to enable the State Engineer to respond to the written notification of the work within the 60-day limit.  Other purposes are to document the basis for the acceptance, and provide a record for evaluating the future performance of the dam and its safe storage level.

Rule 10.2.1  The purpose for requiring the engineer to ascertain the completion of the work is because they are the best qualified to do it.  The record must contain this assurance to validate the safe storage level of the dam.

Rule 10.2.2  The purpose is to create an accurate record of the dam's construction, and to evaluate future performance and safe storage level as well as a public record for future use.

Rule 10.2.3  The purpose is to create a record for evaluation of the future performance of the dam.  If problems occur with the dam, these records will be invaluable in the analysis of the problem and may save the large expense of exploration of the cause of the problem.

Rule 10.2.4  The purpose is to have a basis so as to determine any possible shifting of the dam.

Rule 10.2.5  The basis is Section 37-87-105, C.R.S.. The first filling of a reservoir is the most critical phase of the safety of a dam's performance.  Although every effort has been made to assure the safe design and construction of the dam, unforeseen conditions could exist which could jeopardize the safety of the dam during the initial filling of the reservoir.  The purpose of the rule is to control the filling and monitor the performance, and enable the discovery of any problems and remedy them before the dam could fail.  The consequences of the failure of a minor Low Hazard and NPH dams are considered small, therefore only requiring a visual observation of the dam during filling.

Rules 10.2.6 and 10.3  The basis is Section 37-87-105, C.R.S..  Rule 5 contains the requirements for instrumentation for each class of dam.  The purpose of this rule is to assure that the instrumentation is monitored and the data analyzed.  The data and analysis supplements the safety evaluation of a dam by early detection of movements, stress, or trends which are abnormal in relation to the expected performance of the dam.  It is important that the data be analyzed (graphed) and compared with past performance data for detection of trends (normal or abnormal). The history of performance is an important part of the safety evaluation of a dam.  The analysis must be sent to the State Engineer for review and filing to enable him to evaluate the safe storage level and maintenance of the record in the dam safety files. The evaluation and analysis must continue for the life of the dam.

Rule 10.4  The basis is Section 37-87-105, C.R.S..  The purpose is to maximize the beneficial use of water by allowing temporary storage if a project is substantially complete in the judgment of the State Engineer.  Written request is needed in order to document the basis for the decision of the State Engineer.

Rule 10.5  The basis for the rule is the standard of the dam safety and security standards and emergency response industry.  As a result of the National Dam Safety Program, emergency action planning has become an important part of dam safety programs, because the primary goal of dam safety programs is to reduce the impacts, specifically loss of life, and protect the public against the consequences of dam failure.  Recognizing that enforcing adequate design, construction, operation and maintenance standards do not provide absolute protection from failures, additional protection should be provided, through emergency action planning.  The purpose of the rule is to assure that appropriate plans are developed and submitted for review and filing before the first filling begins.

Rule 11	CONSTRUCTION, MODIFICATION,ALTERATION, REPAIR, AND BREACH OF NON-JURISDICTIONAL SIZE DAMS

Rule 11  The bases for Rule 11, Nonjurisdictional Dams, are Sections 37-87-105, C.R.S., 37-87-107, C.R.S, 37-87-109, C.R.S., and 37-87-125, C.R.S.

Rule 11.1  The basis for Rule 11.1. is Section 37-87-125, C.R.S., which states that any person proposing to construct a reservoir that is nonjurisdictional shall submit notice to the State Engineer prior to beginning any construction.  The purpose of the form is to standardize the format of the notice which facilitates the administration and filing.  The purpose for the 45 day notice is to allow the State Engineer time to evaluate the notice and to respond to the applicant in the event the proposed structure is jurisdictional or could affect the administration of water rights.  The purpose for submitting the form to the Division Engineer is because he is the best qualified to determine whether the proposed structure will affect other water rights.

Rule 11.2  The bases for Rule 11.2 are Sections 37-87-105, C.R.S., 37-87-107, C.R.S, and 37-87-109.  The purpose of this rule is to provide minimum standards for the safety of jurisdictional dams which will be altered to nonjurisdictional size.  The basis for the rule is Section 37-87-105, C.R.S., requiring the approval of alterations to a dam by the State Engineer.

Rule 11.2.1  The purpose of this rule is to prevent loss of life and significant property damage by ensuring the dam is altered properly.  Since the dams are jurisdictional and are being altered, an application must be submitted in accordance with Rule 6 for approval by the State Engineer.

Rule 11.2.2  The purpose of this rule is to prevent small damage to property while providing practical standards which will minimize the owner's cost.  

Rule 11.2.3  The basis for this rule is "Acceptance of Construction of Jurisdictional Size Dams” is Section 37-87-105, C.R.S., which states that no work shall be deemed complete until the State Engineer furnishes to the owner a written acceptance of the work.

Rule 11.3  The purpose of this rule is to provide minimum standards for the repair or breaching of existing non-jurisdictional dams found to be unsafe.  The bases for the rule are Sections 37-87-107, C.R.S. and 37-87-109, C.R.S. "complaints on the safety of a dam," which are the primary reasons for the State Engineer to evaluate the safety of nonjurisdictional dams.

Rule 11.3.1  The purpose for this rule is to provide minimum standards for the repair and breaching of non-jurisdictional size dams found to be unsafe.  

Rule 11.3.2  The purpose for this rule is to prevent loss of life and significant property damage.  The purpose for requiring a professional engineer to prepare the plans is to safeguard life and property.  Since the law does not require that the plans be filed, they do not need to meet the requirements of Rule 5; however, they must be adequate to assure the quality of the repairs.

Rule 11.4  The basis for this rule and its subparts is Section 37-87-105, C.R.S., and standards of other states and dam safety organizations.  The purpose of this rule is to establish minimum standards for flood protection of reservoir dams with the objective of avoiding loss of dams by overtopping as much as possible.  The spillways will also prevent the dams from diverting the floodwaters to adjacent property and preventing damage.  The spillways will also protect against the loss of the dam and loss to the owner.

Rule 11.5   The purpose of this rule is to assure that a jurisdictional size dam is not constructed using a notice of intent to construct a non-jurisdictional size dam procedure.

Rule 12	GENERAL MAINTENANCE, ORDINARY REPAIRS, AND EMERGENCY ACTIONS

Rule 12  The basis of Rule 12.1 through 12.6 is Section 37-87-105(1) and (4), C.R.S., which states in part "General maintenance, ordinary repairs, or emergency actions not impairing safety shall be excluded from the provisions of this subsection (4)."  (Prior approval of plans by the State Engineer is not required.)  The specific differentiations presented in this rule are based on the experience of the State Engineer in making the determination of safe storage level for the several reservoirs in this state.  The purpose of this rule is to allow a distinction to be made by the State Engineer between those actions which are believed to impair the safety of the dam, and those actions that do not impair the safety of the dam and can be done by the owner without prior approved plans.

Rule 12.1.1  The purpose for not requiring approved plans for this work is that removal of brush or tall weeds is usually accomplished by repeated cutting, spraying foliage with herbicides, digging or grubbing, cabling, burning, or grinding and each of these methods has only a superficial effect on the‑structure-and does not impair the safety of the dam.

Rule 12.1.2  The purpose for not requiring approved plans for this work is that cutting of trees and removal of slash from the dam is usually accomplished with chain saws or light excavating equipment and in general this work is expected to have only a surficial effect on the dam and is not expected to impair the safety of the dam.

Rule 12.1.3  The purpose for not requiring approved plans for this work is that rodent control is usually carried out by removing the rodents and then backfilling the rodent holes. In general this work is carried out by hand tools and has only a surficial effect on the dam and is not expected to impair the safety of the dam.

Rule 12.1.4  The purpose for not requiring approved plans for this work is that repair of erosion gullies is usually carried out by first removing vegetation and unsuitable earthen material and then backfilling the affected area with competent material. In general this work is carried out with hand tools or light excavating equipment and has only a surficial effect on the dam and is not expected to impair the safety of the dam.

Rule 12.1.5  The purpose for not requiring approved plans for this work is that surface grading is usually carried out by use of hand tools or a grader.  The effect is usually only surficial and is not expected to impair the safety of the dam.

Rule 12.1.6  The purpose for not requiring approved plans for this work is that placement of additional riprap and bedding in the case of minor damage usually involves only shallow dressing of the earthen embankment, then placement of additional erosion resistant materials.  This work has only a surficial effect on the dam and is not expected to impair the safety of the dam.

Rule 12.1.7  The purpose for not requiring approved plans for this work is that painting, caulking, or lubricating of metal structures is usually carried out with hand tools and affects only the exterior surfaces of the part addressed.  This work is not expected to impair the safety of the dam.

Rule 12.1.8  The purpose for not requiring approved plans for this work is that patching or caulking spalled or cracked concrete is appropriate in areas where the concrete has not suffered structural damage.  This work is preventative in nature and is usually carried out with hand tools and affects only the surface being treated and is not expected to impair the safety of the dam.

Rule 12.1.9  The purpose for not requiring approved plans for this work is that removing accumulated materials from the outlet conduit or outlet or spillway channel generally involves only removal of materials that are not a part of the structure in order to restore designed hydraulic capacities and this work is not expected to impair the safety of the dam.

Rule 12.1.10  The purpose for not requiring approved plans for this work is that this patching work is done to restore wearing surfaces and does not involve structurally significant portions of the dam.  This work is usually carried out with hand tools and has only a surficial effect and is not expected to impair the safety of the dam.

Rule 12.1.11  The purpose for not requiring approved plans for this work is that replacement of mechanical parts of the outlet system which will restore the valves and controls to a satisfactory condition usually involves a replacement in kind of components and does not affect structural integrity or impair the safety of the dam.

Rule 12.1.12  The purpose for not requiring approved plans for this work is that repair or replacement of fences usually requires digging post holes or otherwise providing for the anchoring of the fence posts.  This work has only a surficial effect on the parts receiving the fence and is not expected to impair the safety of the dam.

Rule 12.1.13  The purpose of this rule is to exclude landscaping, including the planting of trees and large vegetation near the dam, from being considered “general maintenance”.

Rule 12.2.  The basis of Rule 12.2. is Section 37-87-105(1) and (4), C.R.S., and the experience of the State Engineer (see Rule 12.1.). The purpose for requiring approved plans is that work having more than a surficial effect on the dam, work having an effect on the structural integrity, or work rehabilitating areas that have already been weakened is expected to impair the safety of the dam if done improperly. Therefore, plans must be approved by the State Engineer prior to commencement of this type of work to assure that the work will meet current safety standards.

Rule 12.3.  The basis of Rule 12.3. is Section 37-87-105(1) and (4), C.R.S. (1973)(1987 Supp.), and the experience of the State Engineer (see Rule 12.1.).  The purpose of this rule is to differentiate between those emergency actions that do impair the safety of the dam and those emergency actions that do not impair the safety of the dam.  This rule identifies those actions that are not expected to impair the safety of the dam.

Rule 12.3.1 The purpose for not requiring prior approval by the State Engineer is that materials are usually stockpiled near or on the dam in a location where they cannot affect its structural integrity or interfere with operation of the dam.  This activity is not expected to impair the safety of the dam.

Rule 12.3.2  The basis for Rule 12.3.2 is Sections 37-87-105 and 37-87-108, C.R.S. and Section 37-87-103, C.R.S..  The purpose for not requiring prior approval by the State Engineer is that lowering of the water level is required to lessen the hydrostatic pressure acting on all portions of the dam located below the water surface elevation.  Generally this activity is not expected to impair the safety of the dam; however, when large releases are going to be made the Division Engineer shall be notified to allow for proper notification to downstream persons and patrol of the stream.

Rule 12.3.3  The purpose for not requiring prior approval by the State Engineer is that armoring eroded areas can prevent further damage to the affected areas, without adversely affecting the dam's integrity.

Rule 12.4.4  The purpose for not requiring prior approval by the State Engineer is that plugging leakage entrances usually involves replacing eroded material, or adding material at the upstream surface of the dam.  This activity is not expected to impair the safety of the dam since it reduces the erosion causing flows through the dam.

Rule 12.3.5  The purpose for not requiring prior approval by the State Engineer is that placing sandbags or temporary earthfill on the crest of the dam or on spillway walls in order to restore freeboard and prevent an overtopping failure is not expected to impair the safety of the dam because the additional loading placed on the structure will have no significant effect on structural stability.

Rule 12.3.6  The purpose for not requiring prior approval by the State Engineer is that diverting water away from the reservoir basin does not directly affect the dam structure.

Rule 12.3.7  The purpose for not requiring prior approval by the State Engineer is that training berms constructed to control flood waters are usually not built on but are adjacent to the dam, and may abut against the structure; however, construction of these berms is not expected to impair the safety of the dam.

Rule 12.3.8  The purpose for not requiring prior approval by the State Engineer is that the placing of ring dikes does not impose any additional stress on the dam.  These ring dikes can regulate piping flows and reduce erosion in order to prevent failure of the dam.

Rule 12.3.9  The purpose for not requiring prior approval by the State Engineer is that removing accumulated materials from the outlet conduit or outlet and spillway channel generally involves only removal of materials that are not a part of the structure in order to restore designed hydraulic capacities to increase outflows in order to prevent failure of the dam.

Rule 12.4.  The basis for Rule 12.4. is Section 37-87-107, C.R.S.  The purpose for requiring prior approval by the State Engineer of actions that can impair the safety of the dam is to avoid the catastrophic consequences of a dam failure.  In the instance when failure is imminent and the water level cannot be lowered by any other means, it is reasonable to allow persons attempting to save the dam to lower the spillway or create a controlled breach because failure through the spillway or controlled breach is not expected to create as large a flood as failure of the dam.

Rule 12.5  The purpose for Rule 12.5 is so that the State Engineer can determine if everything is being done to create as safe of a situation as possible and provide the subsequent notification to administrative and emergency staff. 

Rule 12.6  The basis for Rule 12.6. is the standard of the dam and emergency response industry.  The purpose for requiring emergency action plans is to lessen loss of life and property damage in the event of a dam failure.  Emergency action plans are required for dams whose failure is expected to cause loss of life or significant property damage.  The plan must be implemented in order to lessen loss of life and property damage in the interest of public safety.

Rule 13 	DETERMINATION OF SAFE STORAGE LEVEL

Rule 13  The basis for Rule 13, "Safe Storage Level," is Section 37-87-107, C.R.S., which imposes upon the State Engineer the duty to determine the safe storage level of the reservoirs in the state, as often as he deems necessary, for the purpose of protection of the public.

Rule 13.1  The purpose of this rule is to allow the State Engineer to carry out his duties under Section 37-87-107, C.R.S, and to specify that the owner of a dam shall be bound by the State Engineer's determination of safe storage level.  If the State Engineer has not placed a restriction of storage on a reservoir, the safe storage level is the crest of the principal or emergency spillway, whichever is lower in elevation. The dam has been designed to perform under all anticipated loading conditions when normal reservoir storage is up to but not exceeding the elevation of the spillway crest. 

Rule 13.2  The purpose of this rule is to allow the State Engineer to issue restriction orders to enforce his determination of safe storage level in accordance with Section 37-87-107, C.R.S.  The State Engineer uses information from all reliable sources and will consider engineering evaluations of suspected structural, hydrologic, or hydraulic inadequacies provided by the owner’s engineer.  If these engineering evaluations indicate adequate safety, they may form the basis for removal of an existing storage restriction.

Rule 13.3  The purpose of this rule is to inform the owner that the State Engineer will review his classifications periodically and will require the dam to meet the requirements of these rules for the present classification.  Development often takes place downstream of existing dams, in areas which would be flooded if a failure were to occur.  This may require that a dam be reclassified to accurately reflect the effects of its failure in accordance with the definitions of Rule 4.2.14.  By applying the standards of these rules to the new classification, adequate public safety may be maintained.  The owner will be given a reasonable amount of time to comply if the new standards are more stringent.

Rule 14	SAFETY INSPECTIONS PERFORMED BY THE OWNER’S ENGINEER

Rule 14  The basis for Rule 14 is Section 37-87-107, C.R.S., which requires the State Engineer to determine the safe storage level for dams in the state. Although the State Engineer's staff will normally conduct the safety inspections necessary to make this determination, there may be instances where the dam owner wishes to hire his own engineer for that purpose.  This rule specifies requirements which must be met before the State Engineer will accept the inspection performed by the owner's engineer as a replacement for an inspection which would have otherwise been conducted by members of the State Engineer's staff.  (Note: These formal engineering inspections should not be confused with the informal observations carried out by the owner or his caretaker under Rule 15.2.)

Rule 14.1  The purpose of Rule 14.1 is to prequalify the owner's engineer for safety inspections.  This notification is required so that the State Engineer can ensure that the owner's engineer meets the qualifications of Rule 14.8, and so that the State Engineer may delete the owner's dam from his schedule of dams to be inspected by his staff.

Rule 14.2  The purpose of Rule 14.2 is to ensure that qualified engineers perform the safety inspection.  

Rule 14.3  The basis for Rule 14.3 is Section 37-87-107, C.R.S.  The purpose is to provide the information necessary to allow the State Engineer to make his determination of the safe storage level of the reservoir.  The procedures of this Rule are followed by field engineers on the State Engineer's staff.

Rule 14.4  The purpose of this rule is to assure that safety inspections of existing dams performed by engineers hired by the dam owner are prepared within the policies and standards of the State Engineer.   

Rule 15	DAM OWNER’S RESPONSIBILITY

Rule 15.1  The basis for Rule 15.1 is Section 37-87-107, C.R.S. which specifies that site inspection of dams, as well as the outlet conduit, shall be performed as often as the State Engineer deems necessary or appropriate for the protection of public  health and safety.

The purpose of Type A inspections is to detect developing problems with outlets in a practical manner.  Type A outlet inspections are routine, require no special equipment or expertise, and can easily be performed as a part of any safety inspection conducted in accordance with Section 37-87-107, C.R.S.  

The purpose of Type B inspections is to detect internal problems with outlets that are not detected by Type A inspections.  Type B outlet inspections are intensive and may require significant prior coordination to provide access to the outlet interior, or special equipment to assist in viewing the interior of small conduits.  Experience of the State Engineer and his staff has confirmed that the condition of the outlet is often the critical element in determination of the safety of the dam.

Type B outlet inspections are required at least once every ten years on dams which would cause loss of life (High Hazard) or significant property damage (Significant Hazard) if they were to fail.  The ten-year interval was selected as a reasonable minimum standard, and is based on the State Engineer's experience concerning how rapidly serious outlet problems develop, while recognizing the expense or inconvenience to the dam owner to have the inspection performed.

Specific exceptions to the Type B inspection frequency are provided in order to lessen the financial impact on dam owners by analyzing the need for a safety evaluation of the outlet in accordance with procedures developed by the Bureau of Reclamation.  The rule makes the owner responsible for notifying the State Engineer of opportunities to make an inspection of the outlet when the reservoir is drawn down, and the State Engineer responsible for being responsive.

Rule 15.2  The basis for Rule 15.2 is Section 37-87-104, C.R.S., which specifies that a dam owner may be held liable in the event of failure of his dam.  The purpose is to ensure frequent, informal observations of hazardous dams so that serious developing problems can be quickly detected.

Observations under this rule are informal in nature and are not sufficient of themselves to comply with Section 37-87-107, C.R.S. or meet the requirements set forth in Rule 11.  Since the owner or his representative usually live close to and are typically at the dam on a frequent basis, these informal observations provide a cost effective way to identify serious safety problems, and allow emergency corrective action, before the dam fails.

The required frequency of informal observation is based upon the State Engineer's experience concerning how rapidly serious problems can develop, and upon the consequences of failure of the dam.  Dams which would cause loss of life (High Hazard) or significant property damage (Significant Hazard) if they fail must be observed twice a month when the reservoir level is greater than half the full storage capacity.  This requirement is reasonable when the devastating consequences of failure are considered.  The required frequency of informal observation for Low Hazard dams is less, since the consequences of failure of these darns is not as severe.

This Rule also specifies that the owner of a dam must take responsible action to keep their dam from failing.  The owner represents the first line of defense, conducting informal observations, and these rules require that they deal responsibly with any serious safety problems detected.

The State Engineer's "Dam Safety Manual", 2002, describes inspection methods and provides illustrated tables to assist the dam owner in identifying safety problems.  These manuals have been provided to all owners of jurisdictional dams on record.

Rule 15.3  The basis for Rule 15.3. is Section 37-87-107, C.R.S.  The purpose of this rule is to vary monitoring requirements with the consequences of failure of the dam, and is based upon the principal that dams with the greatest potential for causing serious damage or loss of life must be monitored more closely.

The majority of serious dam failures in Colorado have resulted from uncontrolled leakage, which makes the accurate monitoring of these flows of critical importance for all dams.  Seepage measuring devises are of nominal cost, and can be easily installed by the dam owner.

Monuments to allow monitoring of horizontal and vertical movement are also required on dams which would be expected to cause loss of life if they were to fail (High Hazard).  By surveying the monuments, it is possible to detect subtle movements and to then take action to avoid full failure of the dam.  In view of the disastrous effect of the failure of a High Hazard dam, this minimum instrumentation is reasonable and warranted.

The instrumentation described above was judged to be the most cost effective for the early detection of serious problems which could lead to the failure of the dam.

Another purpose for this rule is to prevent dam failures by early detection of problems. If the monitoring data indicate abnormal changes which indicate serious safety problems at the dam, the dam owner must take immediate action; [he] may not wait for the staff of the State Engineer to review the monitoring data on a routine basis.  This will increase the chance of averting a dam failure.  Because of the disastrous effect of the failure of a High Hazard or Significant Hazard dam, the owner may also be required to have his engineer evaluate all monitoring data to assure early detection of serious problems.

Using information from safety inspections conducted in accordance with Section 37-87-107, C.R.S., the State Engineer may, for good reason, require that added instrumentation be installed, or that more frequent monitoring of existing instrumentation be performed.  This will normally occur when the inspection report identifies specific problems which threaten the safety of the dam, or when existing monitoring devices indicate changed conditions.

Rule 15.4  The basis for Rule 15.4. is Section 37-87-107, C.R.S.  The purpose is to ensure that minor deterioration does not develop into serious problems which threaten the safety of the dam.  As a practical matter, it is usually cheaper in the long run for the dam owner to keep his structure in good repair.  Routine maintenance and minor repair can usually be done by the dam owner or his representative at low cost using equipment and materials on hand.  However, repair of problems which have been allowed to become serious enough to threaten the safety of the dam will require an engineering design approved by the State Engineer.  Special equipment and materials may also be required at a much greater cost.

Rule 15.5  The basis for Rule 15.5 is Section 37-87-107, C.R.S.  The purpose is to ensure that the outlet does not become plugged and thus make it impossible to lower the reservoir in an emergency which threatens the safety of the dam.  A secondary purpose, not directly related to dam safety, is to lessen the possibility of swimmers being drawn into the outlet conduit and killed.

Rule 15.6  The basis for this rule is Section 37-87-104.5, C.R.S.  The purpose of the rule is to make sure the State Engineer knows who the current owner of a dam is so he may effectively administer the Dam Safety Program.

Rule 16	EMERGENCY ACTION PLANS (EAP)

Rule 16.  The basis for Rule 16, "Emergency Action Plans" (EAP), is the standard of the dam safety and emergency response industry.  Language provided in Rule 16 is based upon a review of the current state of the practice of the National Dam Safety Review Board, United States Bureau of Reclamation (USBR), United Sates Army Corps of Engineers (USACE), Federal Emergency Management Agency (FEMA), United States Department of Agriculture, Natural Resources Conservation Service (NRCS) and the Federal Energy Regulatory Commission (FERC).  Rule 16 contains the key elements common to each of the aforementioned organizations in a format readily applicable at the State agency level.

Rule 16.1  The basis is the standard of the dam safety and emergency response industry.  The purpose is to provide additional protection to the public from dam failure and the tragic consequences associated with failure of High Hazard and Significant Hazard dams by requiring the owners to plan for failures. The goal is to prevent or minimize the effects of a failure by advance planning.

Rule 16.1.1  The purpose of the rule is to assure that adequate resources will be at hand that can be mobilized quickly when an emergency exists, and to prevent the failure by identifying materials (or stockpiling them), equipment, and labor to combat a threat to the safety of the dam.  This first line of defense could be sufficient to prevent the failure of the dam.

Rule 16.1.2  The purpose of the rule is to determine the  level of emergency such that the local emergency coordinator to be notified.  The local emergency coordinators are responsible for the public notification and evacuation an accurate assessment of the emergency level is critical to the appropriate response in order to mitigate the loss of life consequences due to the flooding caused by a dam break.  

Rule 16.1.3  The State Engineer must be notified in order to initiate the State’s dam safety emergency response plan.  This plan includes sending an engineer to the dam as quickly as possible to review and aid in the prevention of the dam failure. 

Rule 16.1.4  The purpose for requiring a description of actions necessary to prevent a dam failure incident or to help reduce the effects of a dam failure and facilitate response to an emergency, including, but not limited to, identification of equipment, manpower, and material available for implementation of the plan. 

Rule 16.1.5  The purpose for requiring an inundation map is to identify the areas where people reside which will be impacted by a dam failure.  Local emergency coordinators will use this map and the expected time the flood will take to reach an area to prepare their own emergency response plans in order to evacuate people from the flood zone. 

Rule 16.1.6 The purpose of this rule is to clearly identify the appropriate role for determining the termination of the incident and assuring proper documentation of the incident.

Rule 16.2  The basis is the standard of the industry.  The purpose of the rule is to assure that all the necessary details are in an emergency action plan.  The consequences of the failure (loss of life and/or significant property damage) justify the need to provide a comprehensive up-to-date plan.

Rule 16.3  The basis is the standard of the industry.  The purpose of the rule is to assure that the appropriate local emergency coordinators have input into the names, addresses, and telephone numbers of the persons to be notified in an emergency due to dam-break flooding.  The Colorado Division of Emergency Management (CDEM) will also keep a file of all the plans in order to provide their assistance to the local emergency coordinator in accordance with their charter.

Rule 16.4  The basis is the standard of the industry.  The purpose of the rule is to keep the plans current so they are valid and useable when an emergency occurs, which can be at any time during the life of the dam.

Rule 16.5  The basis is the standard of the industry.  The purpose of this rule is to assure emergency response personnel are fully aware of their roles and responsibilities in the event of dam failure and the emergency action plans is current and up to date.

Rule 17	EXEMPT STRUCTURES

Rule 17  The basis for Rule 17, "Exempt Structures", is Section 37-87-114.5, C.R.S., which exempts certain structures from the provisions of Section 37-87-105 through Section 37-87-114, C.R.S.

Rule 17.1  The basis is Section 37-87-114.5, C.R.S.. The rule is consistent with the applicable statute and is repeated here to provide critical information to the public.

Rule 17.1.1  The purpose of the rule is to identify structures which normally are not designed or operated for storing water.  However, some roadway culverts have been gated after their construction, causing water to be dammed by the road fill.  Since the roadway was not designed to store water, it is considered unsafe for such purpose. Anyone contemplating modifying a road fill for the purpose of storing water is not exempt from having their plans approved by the State Engineer.

Rule 17.1.2  The purpose of the rule is to exempt nonjurisdictional dams and any Low Hazard and NPH diversion dams because they are not expected to cause significant damage if they failed.  All other diversion dams are not exempt because of their potential for damage and loss of life.

Rule 17.1.3  The purpose of the rule is to exempt solid waste disposal facilities where embankments are sometimes constructed from the refuse.  The area behind the embankment, however, is filled in with refuse, preventing the storage of water.  Diversion facilities are also constructed around them, for water quality purposes, thus 
preventing the storage of flood water.

Rule 17.1.4  The purpose of this rule is to exempt water storage facilities where the storage of water is below the natural ground surface and no public hazard exists as a result of a failure of the facility.

Rule 17.2  The basis for this rule is Section 37-87-114.5, C.R.S.  The purpose of the rule is to include structures permitted by the Division of Reclamation, Mining and Safety.

Rule 17.3  The rule agrees with the statute.  Raw and potable water dams, sewage effluent dams, and water treatment sludge dams at uranium mills are not permitted by the Colorado Department of Health and Environment.

Rule 17.4.  The basis is Sections 35-49-101 through 116, C.R.S.  The rule agrees with the statute which exempts Livestock Water Tanks from the provisions of Section 37-87-101 through 108 and 113 through 115, C.R.S. Rule 17.4  The purpose is to distinguish a Livestock Water Tank from a "dam".

Rule 17.5  The basis for the rule is Section 37-87-122, C.R.S..  The rule agrees with the statute which exempts Erosion Control Dams from the provisions of Sections 37-87-101, 102, 104 through 108, C.R.S., and 103, C.R.S..

Rule 18	RESTRICTION OF RECREATIONAL FACILITIES WITHIN REERVOIRS

Rule 18.1  The basis for Rule 18.1, "Restriction of Recreational Facilities Within Reservoirs," is Section 37-87-124, C.R.S.  The rule comports with the statute.  The purpose is to prevent the construction of recreational facilities within reservoirs that would sustain significant damage during operation of the reservoir.

Rule 18.2  The basis is Section 37-87-124, C.R.S.  The rule comports with the statute.  The purpose is to exempt completed facilities from the rule except for enlargements or modification.

Rule 18.3  The basis for the rule is Section 37-87-124, C.R.S..  The purpose of the rule is to allow the State Engineer sufficient time to review the proposed plans, in addition to his other statutory duties.  The requested information is required in order for the State Engineer to evaluate whether or not the proposed facility will meet the requirement of the statute and this rule.

Rule 18.4  The basis for this rule is Section 37-87-124, C.R.S.. The purpose of this rule is to enforce the provisions of the statute.

Rule 19	WAIVER OR DELAY OF ENFORCEMENT OF RULES BY THE STATE ENGINEER

The basis of this rule is Section 37-87-105.  Its purpose is to recognize that under the facts of any particular case, a strict and literal application of these rules may work an unreasonable hardship on the dam owner or unreasonably interfere with the beneficial use of water without significantly affecting dam safety.   In such situations the State Engineer should be able to prevent such unreasonable hardships and limitations on beneficial use of water.

Rule 20	APPEAL OF REQUIREMENTS OR APPROVAL

The basis of Rule 20 is section 1.1.4(2)(vi) of the Division of Water Resources Procedural Regulations, 2 CCR 402-5.  The purpose is to give a person directly impacted by a decision of the State Engineer a method of recourse.

Rules 21 through 25	RULES BY REFERENCE, SEVERABILITY, REVISION, STATEMENT OF BASIS AND PURPOSE INCORPORATED BY REFERENCE, AND EFFECTIVE DATE

The basis and purpose for these rules are self-explanatory.