MEMORANDUM



MEMORANDUM

DATE: December 31, 2018

TO: Gabe Sevigny, PCD-Project Manager

FROM: Steve Kuehster/Beck Grimm, PCD-Engineering

SUBJECT: MS-18-003 – McConnell Minor Sub

First Submittal

___________________________________________________________________________

Engineering Division

Planning and Community Development (PCD)-Engineering reviews plans and reports to ensure general conformance with El Paso County standards and criteria. The project engineer is responsible for compliance with all applicable criteria, including other governmental regulations. Notwithstanding anything depicted in the plans in words or graphic representation, all design and construction related to roads, storm drainage and erosion control shall conform to the standards and requirements of the most recent version of the relevant adopted El Paso County standards, including the Land Development Code (LDC), the Engineering Criteria Manual (ECM), the Drainage Criteria Manual (DCM), and the Drainage Criteria Manual Volume 2 (DCM2). Any deviations from regulations and standards must be requested, and approved by the ECM Administrator, in writing. Any modifications necessary to meet overlooked criteria after-the-fact will be entirely the developer’s responsibility to rectify.

A written response to all comments and return of any redlines is required for review of the re-submittal. The applicant may wish to arrange a meeting between the developer’s team and County staff to review and discuss these comments and prepared revisions/responses prior to the next submittal.

Due to the number of issues and additional information/plans required, more-detailed comments will be provided upon receipt of complete plans and reports and resolution of major issues.

Plat

1. Provide the elevations and floodplain boundary of the 100 year floodplain for each lot per the updated 12/7/2018 Map & LOMR:

2 Identify the ROW dedication for N. Ellicott Highway (A Minor arterial).

3. See cursory electronic redline comments

Final Drainage Report

1. Please update the report per the FEMA map panel number 088041C0585G dated 12/17/2018.

2. Per the Rezoning application it was noted “the subsequent subdivision application the applicant will have to process a LOMR with FEMA to establish the base flood elevation data.”

3. Note the attached checklist for PCD Engineering Final Drainage Report requirements.

4. See cursory electronic redline comments

Attachments/Electronic Files

1. Drainage letter partial redlines.

2. Plat partial redlines.

3. Letter of Intent partial redlines.

4. Final drainage report Checklist

5. Engineering final submittals checklist.

Final Drainage Report (FDR) Checklist

The purpose of the Final Drainage Report is to finalize concepts and to present the design details for the drainage facilities presented in the PDR. Also, any change to the preliminary design concepts, which were incorporated due to review comments by the County, must be presented.

Report Contents

The FDR shall contain all components of the PDR checklist plus additional necessary information relating to the design of specific facilities associated with the development. Such additional information shall include the following:

1) Table of contents, pages numbered.

General Location

2) City and County, and local streets within and adjacent to the subdivision.

3) Township, range, section, ¼ section.

4) Major drainageways and existing facilities.

5) Names or surrounding platted developments.

Description of Property

6) Area in acres.

7) Ground cover (type of trees, shrubs, vegetation).

8) General topography.

9) General soil conditions.

10) Major drainageways.

11) Irrigation facilities.

12) Utilities and other encumbrances.

Major Basin Descriptions

13) Reference should be made to major drainageway planning studies;

such as drainage basin planning studies, flood hazard delineation reports,

and flood insurance studies or maps, if available.

14) A flood plain statement shall be provided indicating whether any portion of

the development is in a designated floodplain as delineated on the current

FEMA mapping.

15) Major basin drainage characteristics.

16) Identification of all nearby irrigation facilities and other obstructions which

could influence or be influenced by the local drainage.

Sub-Basin Description

17) Discussion of historic drainage patterns of the property in question.

18) Discussion of offsite drainage flow patterns and their impact on the

development.

Drainage Design Criteria

19) Reference all criteria, master plans, and technical information used for

report preparation and design; any deviation from such material must be

discussed and justified.

20) Discussion of previous drainage studies (i.e. PDR, drainage basin planning

studies, master plans, flood insurance studies) for the site in question that

influence or are influenced by the drainage design and how the studies

affect drainage design for the site.

Hydrologic Criteria

21) Identify design rainfall.

22) Identify runoff calculation method.

23) Identify design storm recurrence intervals.

24) Identify detention discharge and storage calculation method.

Drainage Facility Design – General Concept

25) Discussion of compliance with offsite runoff considerations.

26) Discussion of anticipated and proposed drainage patterns.

27) Discussion of the content of tables, charts, figures, plates or drawings

presented in the report.

Drainage Facility Design – Specific Details

28) Presentation of existing and proposed hydrologic conditions including

approximate flow rates entering and exiting the subdivision with all necessary calculations.

29) Presentation of approach to accommodate drainage impacts on existing or

proposed improvements and facilities.

30) Presentation of proposed facilities with respect to alignment, material and

structure type.

31) Discussion of drainage impact of site constraints such as streets, utilities,

existing and proposed structures.

32) Environmental features and issues shall be presented if applicable.

33) Discussion of maintenance access and aspects.

34) Discussion and analysis of existing and proposed downstream drainage

facilities and their ability to convey developed runoff from the proposed

development.

35) Presentation of detention storage and outlet design (including reservoir

routings) when applicable.

36) Presentations of all hydrologic and hydraulic calculations including hydraulic

grade line computations as appropriate.

37) Presentation of an accurate, complete, current estimate of cost of proposed

facilities.

38) Presentation of all drainage fees and bridge fees for the property in

question as applicable.

Other Government Agency Requirements

39) Federal Emergency Management Agency (FEMA)

40) Army Corps of Engineers (COE)

41) Colorado State Engineer

42) Colorado Water Conservation Board (CWCB)

43) Others

Drawings/Maps

1) General Location Map: A map shall be provided in sufficient detail to

identify drainage flows entering and leaving the development and general

drainage patterns. The map should be at a scale of 1”=50’ to 1”=2000’.

The map shall identify any major construction (i.e. development, irrigation

ditches, existing detention facilities, culverts, storm sewers, etc.) that shall

influence or be influenced by the subdivision.

2) Drainage Plan: Map (s) of the proposed development at a scale of 1”=20’

3) Floodplain Map FIRM Panel or “Firmette”

4) Soils Map

5) Drainage Plan: Map (s) of the proposed development at a scale of 1”=20’

to 1”=200’ shall be included to identify existing and proposed conditions on

or adjacent to the site in question.

Drainage Plan

6) The drainage plan shall delineate all sub-basins and proposed initial

and major facilities as well as provide a summary of all initial and major

flow rates at design points. All floodplains affecting the site shall be shown.

4) Existing and proposed contours at 2 feet maximum intervals. For

subdivisions involving rural lots greater than 1.0 acre, the maximum interval

may be 5 feet where approved. In terrain greater than 10% - 10 feet.

5) Property lines and existing or proposed easements with purposes noted.

6) All Streets

7) Existing drainage facilities and structures, including irrigation ditches

roadside ditches, drainageways, gutters and culverts, all indicating flow

direction. All pertinent information such as material, size, shape, slope,

and locations shall also be included.

8) Overall drainage area boundary and drainage sub-area boundaries

relating to the subdivision.

9) Proposed type of street sections (i.e., vertical or ramp curb and gutters,

roadside ditch, gutter flow and/or cross pans).

10) Proposed storm sewers and open drainageways, including inlets, manholes,

culverts, and other appurtenances.

11) Proposed outfall point for runoff from the developed area and facilities to

convey flows to the final outfall point without damage to downstream

properties.

12) Routing and summary of initial and major flow rates at various design points

for all storm runoff associated with the property.

13) Path (s) chosen for computation of time of concentration.

14) Details of and design computations for detention storage facilities including

outlet.

15) Location and elevations of all defined 100-year flood plains affecting the

property.

16) Location of all existing and proposed utilities affected by or affecting the

drainage design.

|Engineering Final Submittal Checklist for Electronic Submittals |

|Check |Item: Report/Form, Full-Size Plan (F), 11”x17” Plan (H) |

|Box | |

| |Drainage Report (signed) |

| |Traffic Impact Study (signed) |

| |Grading & Erosion Control Plan (signed) |

| |Street Construction Plans (signed) |

| |Deviation Request (signed) |

| |MS4 Post Construction Form and SDI worksheet |

| |DPW POC: John Chavez |

| |Proof of embankment/pond submittal to State Engineer |

| |ESQCP (signed) DPW POC: John Chavez |

| |* Financial Assurance Estimate, SIA (signed) |

| |* Pond/BMP Maint. Agreement and Easement (signed) |

| |* Operation & Maintenance Manual |

| |Pre-Development Site Grading Acknowledgement and Right of Access Form (signed) |

| |Other: Offsite Easements, Other Permits (FEMA LOMR, USACE, Floodplain…), Conditions of Approval, etc. _ |

|Pre-Construction Checklist: |

| |Work Within the ROW Permit (DPW or CDOT) |

| |* Stormwater Management Plan (SWMP) |

| |Submit to DSD-Inspection 2 weeks prior to precon |

| |* Colorado Discharge Permit (COR:______________________ ) |

| |* County Construction Activity Permit |

| |* CDPHE APEN – (if over 25 ac. or 6 mos.) |

| |* Financial Surety (Letter of Credit/Bond/Collateral/Check) |

| |Construction Permit Fee: |

| |Major Final Plat (CO and/or PBMPS and/or offsite impvts.) | |$ 4,437.00 |

| |(Verify fees with Inspections Supervisor at time of scheduling) | | |

| |Other:______________________________________ |  |  |

| |* - required items to obtain an ESQCP | | | | |

| |** - after recordation | | | | |

| |Permit Fee and Collateral must be separate checks | | | | |

|Post Construction Submittal Checklist: (ECM 5.10.6) |

| |As-Built Drawings |

| |Pond Certification Letter |

| |Acceptance Letter for wet utilities |

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