Construction Sites

1. Plan and Develop Control Measures for Construction Site Activities

Each control measure has a specific function to maintain stormwater quality reducing erosion, reducing runoff, controlling sediment and preventing the discharge of pollutants. Thorough employee training is necessary to ensure that control measures are installed and maintained properly. Carefully schedule construction activities and the installation of control measures to limit soil disturbance and the potential for stormwater pollution. The ADOT Erosion and Pollution Control Manual, CALTRANS Construction Site BMP Manual, and AASHTO Construction Stormwater Field Guide provide guidance on the uses, limitations, design considerations and, maintenance needs of control measures.

Erosion Control Measures 

These control measures act to stabilize the soil preventing it from moving across and off your site.

• Preserving existing vegetation
• Mini benches
• Mulch cover
• Seeding
• Geotextile
• Soil binders
• Interceptor ditch

Runoff Control Measures

These control measures act to slow water down as it moves across and off your site.

• Earth dikes
• Cut to fill slope transitions
• Rock outlet protection
• Erosion protection at structures
• Slope drains
• Check dams

Sediment Control Measures 

These control measures reduce the movement of sediment around and off your site.

• Sediment control berm
• Sediment basin
• Sediment wattle/log
• Storm drain protection
• Curbs inlet protection
• Stabilized site ingress/egress
• Compost sock
• Rock and sediment berms

Good Housekeeping Control Measures 

These control measures prevent contamination from construction materials:

• Maintain vehicles
• Street sweeping
• Store materials in covered areas off the ground
• Vehicle cleaning without the use of soap, solvents, or steam
• Strictly follow recommended usage instructions
• Close dumpster lids at end of day and during rain events
• Protect stockpiles from run-on and run-off
• On-site vehicle fuelingin a designated area with clean-up supplies readily available
• Provide secondary containment for liquids that are 1.15 times the volume of containers within it.
• Stake down portable toilets on level surface away from drainage ways and watercourses

2. Obtain a CGP NOI from ADEQ

To obtain a CGP NOI, apply by registering for a free myDEQ Account and then apply for a CGP NOI. A site specific Stormwater Pollution Prevention Plan (SWPPPP) that meets the requirements of the CGP must be developed prior to applying for a Certificate of Authorization

While completing the application, ADEQ’s 2020 CGPor EPA’s website for construction general permitsmay be useful references. The ADEQ also provides a template for a site specific SWPPP and a checklist (library). PimaMaps – Survey may be used to prepare the general map and site map (PimaMaps QuickStart Guide). Application fees range from $250 to $500.

A construction site disturbs less than 5 acres and that has a rainfall erosivity factor less than 5 may be eligible for a Permit Waiver Certification. When applying for the NOI, myDEQ will calculate the Rainfall Erosivity Factor. The Permit Waiver Certification is time sensitive; if the project continues beyond the dates specified in the waiver certification, the operator must prepared a SWPPP and obtain CGP coverage.

3. Manage Site Your Construction Site for Clean Stormwater

Keep a current SWPPP on-site whenever construction or support activities are active. The SWPPP should identify the stormwater team, construction schedule, summary of potential pollutants, control measures to prevent discharges, records of inspections, maintenance actions, and corrective actions.

Stormwater management is an adaptive process and the SWPPP is a living document. Revise the SWPPP and site map as necessary during the permit coverage to reflect current conditions. Update the SWPPP within 7 days whenever there is a change in design, construction, operation, or maintenance at your site; or a change to the stormwater team.

Perform routine inspections to ensure the SWPPP is implemented correctly and effectively. Additional inspections prior to storm events are advantageous to managing stormwater runoff and associated pollutants. Conduct inspections using the ADEQ CGP Inspection form, or alternative form that documents all the information required by the CGP. During the inspection, follow these recommendations:

• Ensure structural control measures are installed according to SWPPP specs and function as intended
• Assess the effectiveness of good housekeeping practices and pollution prevention procedures
• Observe conditions across the site for evidence of erosion or discharge of pollutants

If a deficiency is observed during the inspection, evaluate the cause of the problem and potential solutions. Implement corrective measures within seven days and update the SWPPP as necessary to reflect current conditions.

The AASHTO Maintenance Stormwater Field Guide provides a quick reference for inspection, control measure maintenance and common operational practices.

4. Follow Ordinances

A series of County ordinances apply within Pima County during construction.

• Remove hazardous rubbish, trash, weeds, debris, & dilapidated buildings (PCC § 7.33.020) 
• Abate environmental nuisance, if present (PCC § 7.45.020)
• Ensure stormwater conveyance during construction in drainageways & floodplain (PCC § 10.44.030.N)
• Minimize loss of soil thru erosion from rainfall or stormwater flow in regulatory floodplains, sheet flood zones, as well as grading and alterations of watercourses (PCC § 16.42.030.A)
• Prevent or reduce erosion in drainage control systems ( PCC § 18.81.040.H)
• Maintain right-of-way during grading in a neat and clean manner (PCC § 18.81.040.L)
• Avoid disposal of used oil is on land, unless permitted/approved by Director. (ARS 49-801,803,811,812)
• Prevent excessive amounts of airborne dust (PCC § 17.16.050)
• Conduct off-site activity, if any, in accordance with Temporary Use Permit (PCC § 18.93.040)

5. Terminate the CGP Coverage with an NOT

To terminate CGP coverage, submit a Notice of Termination (NOT) using myDEQ. Before terminating CGP coverage, at least one of these six conditions must be met:

1. Site has final stabilization (See CGP, Part 3.4.2 for details).
   1. All soil-disturbing activities are complete. All trash and temporary control measures are removed. And either:
      1. Uniform vegetation covers all unpaved areas with a density of 70% of the pre-construction native background
      2. Equivalent permanent stabilization measures (such as riprap, gabions, gravel, or geotextiles) have been employed.
   2. For individual lots in residential construction:
      1. Final stabilization is completed, as described immediately above; or
      2. Temporary stabilization has been completed, including perimeter controls, on a lot and the homeowner has been informed of the need for the final stabilization.
   3. For agricultural land, the disturbed areas have been returned to pre-construction agricultural use.
2. Another operator has assumed control of unstabilized areas with another AZPDES permit.
3. Temporary stabilization at a residence is complete and transferred to owner or an HOA.
4. Planned construction activities were never started.
5. Operator has obtained coverage under another AZPDES permit.
6. Operator qualifies for Alternative Stabilization (See CGP Part 3.4.3 for details)
   1. Sites with additional retention capacity must meet the following conditions*:
      1. There are no outfalls that discharge to a perennial or intermittent water body;
      2. All stormwater generated by disturbed areas of the site is directed to retention basins;
      3. The operator complies with good housekeeping measures;
      4. The operator maintains the capacity of the retention basins; and
      5. The operator determines temporary and final stabilization requirements for the site to reduce or minimize the discharge of sediment and other pollutants, per 3.4.1 and 3.4.2.
   2. Site is returned to pre-construction discharge conditions. The stormwater discharge from the site's pre- and post-construction activities is equal or less than in volume and pollutant load from disturbed areas, as calculated by a professional.
   3. Arid, semi-arid, and drought-stricken areas
      The area is seeded or planted that provides at least 70% native vegetation cover of local undistributed areas within 3 years and, to the extent necessary to prevent erosion on the seeded or planted area, non-vegetative erosion controls have been applied that provide cover for at least 3 years without active maintenance.
      
      
      

* This section does not apply to sites with retention capacity that meets or exceeds the 100 year/ 2-hour storm event, as calculated by an Arizona registered professional engineer, geologist or landscape architect or equivalent.