Fort Garland - Advertisement - Appendix M - Stormwater Management Plan.docx

STORMWATER MANAGEMENT PLAN (SWMP) TEMPLATE 1 ACRE OR MORE ACRES OF DISTURBANCE (6/20/2024)

1. Site Description The Contractor shall comply with all CDOT contractual requirements, and all requirements associated with the CDPS-SCP on this project. The SWMP Administrator for Construction shall update the SWMP to reflect current project site conditions.

A. Project Site Location:

Location or address of construction office:

The site is located south of the intersection of highway 160 and highway 159 in the town of Ft. Garland. More particularly, 29152 Highway 159 Fort Garland, CO 81133.

B. Project Site Description:

[The project will include construction of a 7+1 bay vehicle storage facility, an asphalt parking lot, along with a chain-link boundary fence, manual gates, and utility improvements including an on-site wastewater treatment facility, and a water service line connected to the municipal water system. The project area currently is an undeveloped field that slopes north to south.

C. Proposed Schedule for Sequence for Major Construction Activities:

Stabilize all areas that are not paved or landscaped through establishment of vegetation cover.

Initial erosion control BMPs will be installed, followed by demolition, over lot grading, utility construction, site paving and finally site stabilization and construction activities BMP removal when vegetation is re-established.

D. Acres of Disturbance:

[includes clearing, grading, excavation, stockpiling of fill materials, demolition, areas with heavy equipment/vehicle traffic, installation of new or improved haul roads and access roads, staging areas, dedicated borrow/fill areas and storage that will disturb existing vegetative cover. Round area up to the nearest 100th of an acre or to the nearest sq. ft.]

1. Total area of construction site (LOC (PERMITTED AREA)): 2.5 acres

2. Total area of proposed disturbance (LDA): 2.5 acres

3. Total area of seeding: 0.37 acres

4. Total area of pre-project impervious surface: 3,320 sq. ft.

5. Total area of final impervious surface: 89,984 sq. ft.

E. Existing Soil Data:

Surficial geologic conditions near the site, as mapped by the U.S. Geological Survey (USGS) (Wallace, A.R. and Machette, M.N., 2008), consist of younger stream alluvium sand and gravel deposits of upper Pleistocene age.

Data Source(s): Fort Garland Maintenance Facility Geotechnical Engineering Report, by Terracon Dated April 14, 2025, Project No. 23245154 F. Existing Vegetation, Including Percent of Vegetative Cover:

During design, the SWMP Administrator for Design in consultation with the Engineer will determine if the SWMP Administrator for Design or the SWMP Administrator for Construction will conduct the Vegetation Transects. If the site is disturbed, an Adequate Reference Site(s) may be utilized, refer to the CDPS-SCP.

Vegetation Transect instruction is located on CDOT Landscape Architecture website. https://www.codot.gov/programs/environmental/landscape-architecture/construction-specifications-details-tools-1/207-and-212-psp-required-swmp-development-tools/vegetative-transect-procedure.pdf [SWMP Administrator for Design or SWMP Administrator for Construction is to conduct a survey including general description of existing vegetation prior to any ground disturbance on the project. The SWMP Administrator shall photo-document existing vegetation where all work will be occurring. The SWMP Administrator shall perform the vegetation survey transect(s) and include photo documentation.]

Pre-Construction Date of survey: [XXX] Percent Existing Vegetative Cover: [XXX] Description of existing vegetation: [XXX] Method for determining percent vegetative cover: [Recommend using CDOT Vegetative Transect Procedure; if not used, provide a copy of methodology and have SWMP Reviewer pre-approve.] Include a map or table showing transect locations, photos documenting pre-Construction vegetative cover, and methodology used to determine existing vegetative cover to SWMP Tab 17:

[Transect form is located on CDOT Landscape Architecture website] https://www.codot.gov/programs/environmental/landscape-architecture

Post-Construction Date of survey: ______________ Percent Vegetative Cover: ______________ Description of vegetation:

The method used to determine pre-construction percent cover shall be used to determine post construction percent cover.

Include map or table showing transect locations, photos documenting post-Construction vegetative cover, and methodology used to determine existing vegetative cover to SWMP Tab 17:

[Transect form is located on CDOT Landscape Architecture website] https://www.codot.gov/programs/environmental/landscape-architecture G. Potential Pollutants Sources:

Refer to Potential Pollutant Sources in SWMP Section 4A. The SWMP Administrator for Construction shall prepare a list of all potential pollutants and their locations in accordance with subsection 107.25.

H. Drainage Patterns and Receiving Water(s):

1. Description of drainage patterns from the Site:

The site generally drains to the south. There is a roadside drainage ditch along highway 159 on the west side of the project area.

2. Names of immediate and ultimate receiving water(s) on site:

The site outfalls to Garland Ditch south of the project area, which flows east.

3. Description of all stream crossings located within the Limits of Construction:

No known stream crossings are located within the construction site boundary.

Location [Station or Mile Post]

I. Allowable Non-Stormwater Discharges:

Uncontaminated Springs

Concrete and Masonry Washout Water (in-ground washout structure)#

Landscape Irrigation Return Flows

Discharges from Diversions of State Waters

Emergency Fire Fighting

Discharges to the ground of water used to wash vehicles, equipment, and external buildings

#Concrete and masonry washout water associated with the washing of concrete and masonry tools and concrete mixer chutes can be discharged to the ground if site is managed accordingly to prevent the water from leaving the site as surface runoff or reaching receiving waters. Soaps and solvents shall not be added to concrete and masonry washout water.

J. Diversion Criteria:

1. Is a diversion planned for the Site? ______ No ______.

2. If yes, complete information below:

a. What is the 2-year peak flow for the waterway being diverted (cubic feet per second)?

b. What are the monthly averages if available? (provide averages for Jan-Dec if available)

c. What is the upstream contributing drainage area and imperviousness?

d. A method statement must be prepared by the Contractor and approved by CDOT for each diversion. Diversion structures must minimize soil transport and erosion within the entire diversion, minimize erosion during discharge, and minimize run-on into the diversion and meet the conditions in the SCP.

e. If the conditions in the SCP cannot be met and an alternative is required, CDOT must approve the alternative and then it must be submitted and approved by CDPHE’s Water Quality Control Division prior to implementation.

2. Site Map Components:

Pre-construction

A. Project Construction Potential Site Boundaries:

Project boundaries are shown on sheets C301, C302 & C303

B. Flow Arrows that Depict Stormwater Flow Directions On-Site, Run-On and Runoff Direction:

Flow arrows are shown on sheets C301, C302 & C303

C. All Areas of Ground Surface Disturbance:

Areas of ground surface disturbance are shown on sheets C301, C302 & C303 and are delineated by limits of Disturbance (LOD)

D. Areas of Cut and Fill:

Cut & Fill will be minimal.

E. Areas Used for Storing and Stockpiling of Materials, Staging Areas (field trailer, fueling, etc.) and Locations of All Waste Storage and Batch Plants Including Masonry Mixing Stations:

Stockpiles for material shall be located by the contractor and location may vary depending on current work areas but shall be noted on Sheet C301 when location identified during construction. All stockpiles shall be protected with corresponding BMPs.

F. Location of All Structural Control Measures Identified in the SWMP:

SWMP Structural BMPs/Control Measures are shown on sheets C301, C302 and C303 and include silt fencing, concrete washout area, vehicle tracking control pad, and seeding and mulching

G. Location of Non-Structural Control Measures as Applicable in the SWMP:

Non-structural BMPs shall be located by the contractor and location shall be recorded on the Stormwater Management Plan sheets

H. Springs, Streams, Wetlands, Diversions, And Other State Waters Within or Bordering the Site, Including Areas That Require Pre-Existing Vegetation Be Maintained Within 50 Feet of A Receiving Water:

There are no known springs, streams or wetlands on the site

I. Locations of All Stream Crossing Located Within the Limits of Construction:

There are no known streams on the site

J. Protection of Trees, Shrubs, Sensitive Habitat, and Cultural Resources:

There are no known trees, shrubs, sensitive habitats and/or cultural resources on the site.

K. Locations of Pumped Stormwater Including Intake and Discharge Points and Locations of Dewatering Activities No known pumped stormwater is located within the site.

3. Qualified Stormwater Managers:

A. SWMP Administrator for Design:

CDOT Certified Individual responsible for developing SWMP Plan Sheets and SWMP Site Maps during the design phase.

[The 207 and 212 require that topsoil testing and the top-soil amendment requirements be completed by the SWMP Administrator for Design. For additional information see the SWMP development tools on the Landscape Architecture Section Website https://www.codot.gov/programs/environmental/landscape-architecture/207-and-212-psp-required-swmp-development-tools-1

Email: bcamphouse@ahceinc.com 12596 W. Bayaud Avenue #200 Lakewood, Colorado 80228 A5C42B28

B. SWMP Administrator for Construction: (As defined in Section 208) The Contractor shall designate a SWMP Administrator for Construction upon accepting co-permittee of the permit. The SWMP Administrator for Construction shall become the operator for the SWMP and assume responsibility for all design changes to the SWMP implementation and maintenance in accordance to 208.03, the SWMP shall remain the property of CDOT. The SWMP Administrator for Construction shall be responsible for implementing, maintaining, and revising SWMP, including the title and contact information. The activities and responsibilities of the SWMP Administrator for Construction shall address all aspects of the project’s SWMP. (Update the information below for each new SWMP Administrator for Construction) (A copy of current TECS Certification must be included in the SWMP.)

C. Erosion Control Inspector: (As defined in Section 208) The Contractor shall designate an Erosion Control Inspector. The Erosion Control Inspector shall complete duties in accordance with subsection 208.03(c) (Copy of current TECS Certification must also be included in the SWMP.)

Certification #

D. Permanent Stabilization Subject Matter Expert: This qualified individual will be either a Regional Environmental Staff member, or an Independent Contractor Controller (Independent Assurance Program). This expert is a project team leader responsible for ensuring project adherence to requirements of the 207 and 212 Project Special Provisions as follows and will be available for questions regarding permanent stabilization requirements.

[See the Construction Phase Inspection and Verification Checklist on the Landscape Architecture website for regional contacts to address revegetation questions:

https://www.codot.gov/programs/environmental/landscape-architecture/assets/inspection-and-verification-checklist-for-roadside-revegetation.pdf]

1. Review the Topsoil Management Plan and the Permanent Stabilization Site Maps.

2. Attend the Environmental Pre-Construction Conference.

3. Coordinate the Site Pre-Vegetation Conference.

4. Review and recommend approval of products.

5. Attend the Partial Landscape Completion Walkthrough.

6. Attend the Final Landscape Completion Walkthrough.

4. Stormwater Management Controls for Initial Construction Activities Associated with Water Quality The Contractor Shall Perform the Following:

A. Potential Pollutant Sources:

Evaluate, identify, locate, and describe all potential sources of pollutants at the site in accordance with subsection 107.25, CDPS-SCP, and place in the SWMP. All control measures related to potential pollutants shall be shown on the SWMP Site Map by the Contractor’s SWMP Administrator for Construction.

B. Offsite Drainage (Run on Water):

Describe and record control measures on the SWMP Site Map that have been implemented to address off site run-on water in accordance with subsection 208.03.

C. Vehicle Tracking Control:

Control measures shall be implemented in accordance with subsection 208.04.

D. Perimeter Control:

1. Temporary control measures shall be installed prior to commencing construction activities associated with water quality in accordance with subsection 208.04.

2. Perimeter control may consist of berms, silt fence, erosion logs (sediment control logs), existing landforms, or other control measures as approved.

5. During Construction Responsibilities of the SWMP Administrator for Construction: Considered a “living document”, the SWMP is continuously reviewed and modified throughout the construction phases. During construction, the SWMP Administrator for Construction shall have full responsibility to maintain and update the SWMP in accordance with subsection 208.03(c).

During construction, indicate how items that were not addressed during design are being handled in construction. If items are covered in other sections of the SWMP, indicate below what section the discussion takes place.

A. Materials Handling and Spill Prevention and Response Plan: Prior to commencing Construction Activities Associated with Water Quality, the Contractor shall submit a Spill Response Plan. Materials handling and Spill Response Plan shall be in accordance with subsection 208.06.

B. Other CDPS Permits or Guidance Documents: List applicable CDPS permits or guidance documents associated with the permitted site and activities.

C. Stockpile Management: Shall be done in accordance with subsections 107.25 and 208.07.

D. Concrete Washout: Concrete and masonry washout water or waste from field laboratories and paving equipment shall be contained in accordance with subsection 208.05.

E. Saw Cutting: Shall be done in accordance with subsections 107.25, 208.02, 208.04, 208.05.

F. Street Sweeping: Shall be done in accordance with subsection 208.04.

6. Inspections A. Form 1176 Inspections shall be in accordance with subsection 208.03(c).

B. Permanent Stabilization Inspections shall be in accordance with subsections 208.04(e)4 and 208.10.

7. Control Measure Maintenance At any time, regardless of the inspection schedule, CDOT or the Contractor shall identify control measures requiring corrective action. Identified noncompliance shall be corrected immediately, but no later than 2 calendar days from the time of observation. Corrective actions shall be in accordance with subsection 208.04(f).

8. Record Keeping Records shall be kept in accordance with subsection 208.03(d).

9. Temporary, Permanent Stabilization and Long-Term Stormwater Management The Contractor shall comply with all temporary stabilization and permanent stabilization requirements in accordance with subsection 208.04(e).

A. Seeding Plan:

Work with Region Environmental Specialist, Biologist, wetland specialist or Regional or Headquarter Landscape Architect to develop project seed mix(es).

The following seed mix(es) and rates are for drill seeding method as shown on the Permanent Stabilization Site Maps shall be used:

Drill Seed PLS lbs/acre Broadcast/Hydro

B. Seeding Application Method:

The following seeding method shall be used for all areas shown on the Permanent Stabilization Site Maps. Soil compaction shall be minimized for areas where permanent stabilization will be achieved through vegetative cover.

Total

C. Soil Stabilization Methods:

Minimum soil stabilization methods (attached mulch) for all disturbances to receive seeding.

[Select methods used on the Permanent Stabilization Site Maps and delete all others. Add additional soil stabilization methods with an approved project special specification. Round quantities up to the nearest whole number]

1. Apply a minimum of 2 tons/ac certified weed free hay or 2 ½ tons/ac of certified weed free straw and mechanically crimp into the soil in combination with natural mulch tackifier in accordance with Section 213. Prior to winter shutdown or the summer seeding window closure: Uncompleted slopes shall be mulched with 2 tons of mulching (weed free) per acre, mechanically crimped into the topsoil in combination with an organic mulch tackifier in accordance with Sections 208 and 213.

2. Apply Spray-on Mulch Blanket hydraulically in accordance with Section 213.

3. Apply Bonded Fiber Matrix hydraulically in accordance with Section 213.

4. Install Soil Retention Blankets in accordance with Standard Plan M-216-1 and Section 216.

D. Special Requirements:

1. Soil amendments, seedbed preparation, and permanent stabilization mulching shall be accomplished within four working days of placing the topsoil on the de-compacted civil subgrades. If placed topsoil is not mulched with permanent stabilization mulch within four working days, the Contractor shall complete temporary stabilization methods in accordance with subsection 208.04(e) at no additional cost to the Department.

2. Complete permanent stabilization mulching within 24 hours of hydraulic application of native seed.

3. The Contractor shall submit a proposed Permanent Stabilization Phasing Plan to the Engineer for approval showing how implementation of SWMP Permanent Stabilization Plans will minimize damage to seeded areas.

E. Soil Amendment Requirements: Minimum amendment material requirements for all disturbances to receive seeding.

[Select seeding and topsoil generation method(s) used on the Permanent Stabilization Site Maps and delete all others. If more than one revegetation unit was sampled and produced different soil amendment requirements add additional tables as necessary. Round quantities up to the nearest whole number] [select either High or Low N formulations for organic fertilizer based on recommendation from CDOT’s Amendment Calculator].

0.37 Total Acres of Seeding (Native) Hydraulic (Pay Item 212-00708)

F. Permanent Stabilization Application Under Structures:

Under structures, shade patterns should be considered and the use of Median Cover Material (Stone) or other stabilized options with an approved Project Special Provision should be used. See SWMP Site Map for locations.

G. Reseeding Operations/Corrective Stabilization:

Prior to stormwater construction work partial acceptance.

1. All seeded areas shall be reviewed by the SWMP Administrator for Construction and or Erosion Control Inspector for bare soils caused by surface or wind erosion. Bare areas caused by surface or gully erosion, blown away mulch, etc. shall be re-graded, seeded, and have the designated mulching applied as necessary, at no additional cost to the project.

2. The Contractor shall maintain seeding/mulch/tackifier/blanket/TRM, mow to control weeds or apply herbicide to control weeds in the seeded areas, at no additional cost to the project.

H. Location and Description of Planned Permanent Control Measures:

Is Permanent Water Quality Required. Yes ______ No ___X___.

10. Prior to Project Final Acceptance A. When directed by the Engineer, removal and disposal of temporary control measures shall be included in the cost of work.

B. At the end of the project, all ditch checks shall consist of either temporary erosion logs (sediment control logs) (or equivalent) or permanent riprap.

C. All storm drains shall be cleaned prior to the Final Acceptance of the project. If required, include work in 202-04002 Clean Culvert. [**Check with Region Water Quality staff to see if Clean Culvert PSP is needed and what Pay Item to use.**]

D. Refer to subsection 208.10 for Items to be completed prior to requesting partial acceptance of water quality work.

Template Revised: 6.20.2024

11. Narratives Control Measure Matrixes During Construction:

1. Control measure narratives have been included for the CDOT Standard Specifications and Standard Plan M-208 and M-216 along with any non-standard control measures approved during the design process. If a Non-Standard Control Measure not included in the SWMP is proposed and approved by the Engineer, the SWMP Administrator for Construction shall: Place an “X” in the column “M-208 Standard or ‘X’ for Non-Standard” and complete a Non-Standard Control Measure Specification and Narrative. The Narrative shall include drawings, dimensions, installation information, materials, implementation processes, control measure-specific inspection expectations, and maintenance requirements of the control measure. The appropriate “X” shall also be added to the implementation phase(s).

2. The SWMP Administrator for Construction shall place an “X” in the column “In Use On Site” when the control measure has been installed.

3. A “B” in the “Initial Activities” column indicates that the control measure shall be installed before construction activities associated with water quality commence. Locations and quantities will be discussed during the Environmental Pre-Construction Conference with the Regional Water Pollution Control Manager.

Structural Control Measures that may be potentially used on the project for erosion and sediment control; practices may include, but are not limited to the following:

Application, Control measure

Stabilization

Culvert Inlet/Outlet Protection Erosion logs (sediment control logs), aggregate bags

Stockpile Protection Temporary berm, erosion logs (sediment control logs), aggregate bags*

X

Perimeter Control Erosion logs (sediment control logs), silt fence, temporary berms

Outlet Protection Riprap, or approved other

Concrete Washout In-ground or fabricated

Other

Non-Structural Control Measures that may be potentially used on the project for erosion and sediment control; practices may include, but are not limited to:

Erosion control devices are used to limit the amount of soil loss on site. Sediment control devices are designed to capture sediment on the project site. Construction controls are control measures related to construction access and staging. Control Measure locations are indicated on the SWMP Site Map.

Application, Control measure

Initial Activities

Stabilization

Vegetative Buffer Strip

Finishing component for filtering sediment-laden runoff from disturbance area. Area within CDOT ROW or temporary easement to be identified on SWMP prior to construction activities associated with water quality starting. Upgradient control measures must be installed immediately adjacent to vegetative buffers.

Grading Applications (Landform)

Topsoil Management Stockpile/Salvage Stockpile

X

X

X

Seeding Permanent (Native Perennial)

Permanent Stabilization of disturbance and to reduce runoff and control erosion on disturbed areas.

X

Soil Retention Blanket (SRB)

Turf Reinforcement Mat (TRM)

X

Other

12. Tabulation of Stormwater Quantities A. Control Measure sediment removal and disposal shall be paid for as: 208 Removal and Disposal of Sediment (Equipment) and 208 Removal and Disposal of Sediment (Labor). All other control measure maintenance shall be included in the cost of the control measure.

B. It is estimated that 20 hours of blading (140-250 horsepower), dozing (130-250 horsepower) and/or combination loader (80-125 horsepower) may be required for miscellaneous erosion control work as directed by the Engineer. Work shall be paid for as: 203 Blading, 203 Dozing and/or 203 Combination Loader]

PSP

Spec.

Const.

Interim Const.

Permanent Stabilization *Total Quantity

4,000

4,000

*It is anticipated that additional control measures and control measure quantities not shown on the SWMP Site Maps shall be required on the project for unforeseen conditions and replacement of items that are beyond their useful service life, see subsections 208.03 and 208.04. Quantities for all control measures shown above are estimated and have been increased for unforeseen conditions and normal control measure life expectancy. Quantities shall be adjusted according to the conditions encountered in the field as directed and approved by the Engineer. Payment shall be for the actual work completed and material used.

**Pay Item 208-00071 is included for anticipated maintenance of vehicle tracking pads based on the service life of the control measure in the field. The use of the material shall be directed and approved by the Engineer.

13. Biological Impacts and Dewatering A. Environmental Impacts:

1. Wetland Impacts: No

2. Stream Impacts: No

3. Threatened and Endangered Species:

No species are anticipated to be impacted by the project.

B. Dewatering:

(Not covered under the CDPHE guidance document Low Risk Discharge Guidance Discharges of Uncontaminated Groundwater to Land): https://drive.google.com/open?id=17ck1ZJojHSacJ_wxp2FfUr4rAxNgVWZv

1. Dewatering: Refer to other environmental permits in accordance with subsection 107.02 and the permits contained in Tab 16 of the SWMP.

2. If groundwater does not meet water quality standards for receiving water a separate CDPS Dewatering Permit shall be obtained by the Contractor from CDPHE in accordance with subsections 107.02 and 107.25.

14. Notes [Use of this section may include, but is not limited to, documenting assumptions made in cost estimating]