(Ordinance 2012-10 adopted 8/21/12)
This Chapter discusses the five-step development process. Local governments will integrate these processes into their current process by the addition of local provisions.
A formal integrated Stormwater Management Development Process shall be implemented to meet the stormwater management goals and to see that local stormwater guidelines and requirements are implemented. The process shall include the steps, meetings, and documents that must be met by the developer. The five-step process described herein includes the following:
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The iSWM Plans: The iSWM Plans are the documents that summarize the data collected in steps 1 and 2 and are shown on the conceptual/preliminary and final plans that must be submitted to the municipality as part of steps 3, 4, and 5. Each submittal must follow the criteria outlined in Sections 14.2.0 and 14.3.0. Submittals shall include information in accordance with the checklists that are included in Section 14.5.0.
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The iSWM Construction Plan: The iSWM Construction Plan is the document that uses data collected in steps 1 and 2 to protect water quality during construction. It is submitted to the municipality with the Final iSWM Plans in Step 4. An overview of the iSWM construction plan content is covered in Section 14.2.2. More detailed criteria for the iSWM Construction Plan are outlined in Section 14.4.0.
The iSWM Plans and iSWM Construction Plan are a subset of the overall development process that occurs throughout the planning and development cycle of a project and then continues after construction is completed via regular inspection and maintenance of the stormwater management system.
In addition to these plans, stormwater master plans are an important tool used to assess and prioritize both existing and potential future stormwater problems and to consider alternative stormwater management solutions. Local governments may have individual watershed plans, or several governments may work cooperatively to develop a unified approach to watershed planning, development controls, permit compliance, multi-objective use of floodplain and other areas, and property protection. Refer to the Local Provisions in Step 1 under Section 14.2.2 where regional approaches (if any) are identified.
Local Provisions: Conceptual, preliminary, and final iSWM Site Plans and supporting technical data will be submitted for review and approval to the City of Azle.
(Ordinance 2012-10 adopted 8/21/12)
This section describes the typical contents and general procedure for preparing iSWM Plans and the iSWM Construction Plan. The level of detail involved in the plans will depend on the project size and the individual site and development characteristics. Figure 2.1 lays out the five-step process. Each of the following steps builds on the previous steps to result in the Final iSWM Site and Construction Plans:
Step 1 - Review Local Requirements and Municipality’s Processes
Step 2 - Collect Data and Perform Site Analysis
Step 3 - Prepare Concept/Preliminary iSWM Plans
Step 4 - Prepare Final iSWM Plans and iSWM Construction Plan
Step 5 - Prepare Operation and Maintenance Plans
Figure 14.2.1 iSWM Flowchart
Local Provisions: Prior to Certificate of Occupancy being issued, a Final Grading Certificate prepared by an engineer or the contractor, as appropriate shall be submitted. The Final Grading Certificate shall state that the site grading and drainage improvements are constructed in substantial compliance with the approved plans. If the improvements were not constructed in substantial compliance with the plans, appropriate documentation shall be provided to substantiate any changes. If changes were made to public facilities, the City shall require an engineer to document field changes by submitting certified as-built plans.
Step 1. 
Review Local Requirements and Municipality Processes
The site developer shall become familiar with the local stormwater management, development requirements and design criteria that apply to the site. These requirements include:
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iSWM Criteria Manual for Site Development and Construction (this manual including all local provisions)
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Available online iSWM Program documents
 
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iSWM Technical Manual
 
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iSWM Tools
 
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iSWM Program Guidance
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State and Federal Regulatory Requirements
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Other Local Municipal Ordinances and Criteria
 
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Platting Procedures
 
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Zoning Requirements
 
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Development Codes and Procedures
 
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Tree and Landscape Requirements
 
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Special Use Permits
 
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Drainage Master Plans and Watershed Plans
 
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Erosion Control Plans
 
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Floodplain Ordinances
 
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Grading Plan Requirements
 
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Construction/Building Permit Notifications and Requirements
Information regarding the above items can be obtained from this manual or at a pre-submittal (or similar) meeting with the municipality.
A critical part of any project involves the proposed development working closely with various departments within the municipality. Integrating the stormwater practices with other regulatory requirements will promote a sustainable development.
Opportunities for special types of development (e.g., clustering) or special land use opportunities (e.g., conservation easements or tax incentives) must be investigated. In addition, there may be an ability to partner with a local community for the development of greenways or other riparian corridor or open space developments.
All applicable State and Federal regulatory requirements must be met.
Local Provisions: NONE
Step 2. 
Collect Data and Perform Site Analysis
Using field and mapping techniques approved by the municipality, the site engineer shall collect and review information on the existing site conditions and map the following site features:
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Topography
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Drainage patterns and basins
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Intermittent and perennial streams on-site and off-site waters that will receive discharges from the proposed development
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Soil types and their susceptibility to erosion
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Ground cover and vegetation, particularly unique or sensitive vegetation areas to be protected during development
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Existing development
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Existing stormwater facilities on-site and off-site facilities that will receive discharges from the proposed development
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Property lines, adjacent areas and easements
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Wetlands and critical habitat areas
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Boundaries of wooded areas and tree clusters
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Floodplain boundaries
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Steep slopes
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Required buffers and setback along water bodies
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Proposed stream crossing locations
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Other required protection areas
The site analysis shall be summarized in the conceptual/preliminary iSWM Plans along with any other supporting documents. The data collected and analyzed during this step of the development process shall be used as the starting point for preparing the iSWM Plans and the iSWM Construction Plan.
Local Provisions: NONE
Step 3. 
Prepare Conceptual/Preliminary iSWM Plans
Conceptual iSWM Plan
Based on the review of existing conditions and site analysis, the design engineer shall develop and submit a Conceptual iSWM Plan for the project. The Conceptual iSWM Plan allows the design engineer to propose a potential site layout and gives the developer and local review authority a “first look” at the stormwater management system for the proposed development. The following steps shall be followed in developing the Conceptual iSWM Plan with the help of the Checklist for Conceptual iSWM Plans found in Section 14.5.0 of this manual:
1. 
Use integrated Site Design Practices (Section 14.3.2.2) as applicable to develop the site layout, including:
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Preserving the natural feature conservation areas defined in the site analysis
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Fitting the development to the terrain and minimizing land disturbance
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Reducing impervious surface area through various techniques
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Preserving and utilizing the natural drainage system wherever possible
2. 
Determine the credits for integrated Site Design (Section 14.3.2.2) and water quality volume reduction (Section 14.3.2.3) as applicable, to be accounted for in the design of structural and nonstructural stormwater controls on the site.
3. 
Calculate conceptual estimates of the locally required focus area design requirements for water quality protection, streambank protection, and flood mitigation (Sections 14.3.2, 14.3.4, 14.3.5) based on the conceptual plan site layout.
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Perform screening and conceptual selection of appropriate temporary and permanent structural stormwater controls (Section 14.3.8 and Section 14.4.0) and identification of potential site locations.
It is extremely important at this stage that stormwater system design is integrated into the overall site design concept in order to best and most cost-effectively reduce the impacts of the development as well as provide for the most cost-effective and environmentally sensitive approach. Using hydrologic calculations, the goal of mimicking pre-development conditions can serve a useful purpose in planning the stormwater management system.
Local Provisions: Conceptual iSWM Site Plans shall be prepared and submitted to the City of Azle in the initial planning stages of a land development project with a Conceptual iSWM Site Plan. In general, the engineer and planner will follow the conceptual iSWM Site Plan guidelines as presented in Section 14.2.2 Step 3, as applicable to Azle. Water quality and streambank protection detention requirements are part of the City of Azle criteria. A conceptual drainage study and Conceptual iSWM Site Plan for any proposed development shall include at a minimum the information listed in the Engineer’s Checklist for Conceptual iSWM Site Plan shown in Chapter 5, Appendix A - City of Azle Detailed Checklists and Forms.
A Grading Permit is required prior to any construction or grading activity involving 0.1 acres or more of disturbed surface area, if disturbed areas are located within Floodplain and/or drainage easement. This Grading Permit will be approved for earthwork only, will be at the risk of the owner/developer, and will require compliance with any other required permits or approvals including floodplain and SWPPP, as applicable.
Preliminary iSWM Plans
The Preliminary iSWM Plan ensures that requirements and criteria are complied with and opportunities are taken to minimize adverse impacts from the development. This step builds on the data developed in the Conceptual iSWM Plan by refining and providing more detail to the concepts identified. If no Conceptual Plan is submitted, it shall be part of the Preliminary iSWM Plan. The checklist for Preliminary iSWM Plan in Section 14.5.0 outlines the data that shall be included in the preliminary iSWM Plan.
The Preliminary iSWM Plan shall consist of maps, plan sheets, narrative, and supporting design calculations (hydrologic and hydraulic) for the proposed stormwater management system. The completed Preliminary iSWM Plan shall be submitted to the local review authority for review and comment.
Local Provisions: A Preliminary Drainage study and iSWM Site Plan for any proposed development must accompany a preliminary plat submitted for development review, and shall include at a minimum the information listed in the Engineer’s Checklist for Preliminary iSWM Site Plan shown in Chapter 5, Appendix A - City of Azle Detailed Checklists and Forms. The study will include a downstream assessment of properties that could be impacted by the development. These studies will include adequate hydrologic analysis to determine the existing, proposed, and fully developed runoff for the drainage area that is affected by the proposed development and will include hydraulic studies that define the “adequate outfall.” The study, as part of the development of the iSWM Site Plan, shall address existing downstream, off-site drainage conveyance system(s) and define the discharge path from the outlet of the on-site stormwater facilities, to the off-site drainage system(s) and/or appropriate receiving waters. It will include a capacity analysis of all existing constraint points such as pipes culverts/bridges, or channels from the point of stormwater discharge of the development downstream to an “adequate outfall.” For drainage areas of 100 acres or less, the downstream assessment will be limited to an “adequate outfall point,” determined by the study, or the 10% rule (see the iSWM Hydrology Technical Manual, Section 2.4). For drainage areas larger than 100 acres, the “adequate outfall point” will be defined by the detailed hydrologic and hydraulic analyses. This preliminary drainage study and Preliminary iSWM Site Plan will include:
1. A topographical map of the entire watershed (not just the area of the proposed development) generally not smaller than 1" = 200' (or other such scale approved by City of Azle), delineating the watershed boundary(s) and runoff design point(s), existing and proposed land use and zoning, and the size and description of the outfall drainage facilities and receiving streams.
2. Computation tables showing drainage areas, runoff coefficients, time of concentration, rainfall intensities and peak discharge for the required design storms, for both existing and proposed (ultimate development) conditions, at all design points for each component of the stormwater system (streets, pipes, channels, detention ponds, etc.).
3. Any proposed changes to watershed boundaries (i.e. by re-grading, where permissible by Texas Water Code). If significant changes to watershed boundary are made, more extensive analyses of downstream impact and mitigating detention will be required and a variance obtained from the Storm Water Manager.
4. FEMA Flood Hazard Areas, if applicable.
5. In addition any required Corps of Engineers’ Section 404 permits, Conditional Letters of Map Revision (CLOMR), Letters of Map Revision (LOMR) or other permits relating to lakes and streams required by any federal, state or local authorities. These must be documented in the Drainage Study.
6. Detailed off-site outfall information. This shall include the presence of existing or proposed drainage structures, bridges or culverts; documentation of existing versus proposed developed site as well as ultimate runoff, identification of downstream properties which might be impacted by increased runoff, and proposed detention or other means of mitigation. Downstream impacts shall generally be delineated identified to a point where the drainage from the proposed development has no impact on the receiving stream or on any downstream drainage systems within the “zone of influence.”
7. Report with technical documentation.
8. A Grading Permit is required prior to any construction or grading activity involving 0.1 acres or more of disturbed surface area and if disturbed surface areas are located within floodplain or drainage easement. This Grading Permit will be approved for earthwork only[,] will be at the risk of the owner/developer, and will require compliance with any other required permits or approvals including floodplain and Landscaping (Section 29 [of the zoning ordinance]) and SWPPP, as applicable.
Step 4. 
Prepare Final iSWM Plans and iSWM Construction Plan
The Final iSWM Plans and iSWM Construction Plan shall be prepared together and submitted to the local review authority for approval prior to any soil disturbance or other construction activities on the development site. The Final iSWM Plans add further detail to the Preliminary iSWM Plan and reflect changes that are requested or required by the local review authority.
The Final iSWM Plans and iSWM Construction Plan, as outlined in the final iSWM Plan checklist in Section 14.5.0, shall include all of the revised elements of the Preliminary iSWM Plans as well as a landscape plan, operation and maintenance plan, and any permits/waiver requests.
Local Provisions: A Final Drainage Study and iSWM Site Plan for development of all or a portion (i.e. phase one or phase two, etc.) of the overall development shall be prepared and submitted to the City of Azle. This submittal shall include at a minimum the information listed in the Engineer’s Checklist for Final iSWM Site Plan shown in Chapter 5, Appendix A - City of Azle Detailed Checklists and Forms, including:
1. Conformance with the Preliminary iSWM Site Plan and Study.
2. Submission of detailed drainage calculations and detailed design plans.
3. The submission of a cover sheet signed by the Storm Water Manager indicating the approval of the detailed construction drawings for the proposed development is sufficient to clear a plat drainage study comment.
4. Final drainage studies shall be approved based on the submission of a signed cover sheet and drainage map with calculations from the approved engineering construction drawings. Where City approval of construction plans is not required, the above information required for preliminary drainage studies, as well as construction plans for any drainage improvements, shall be submitted.
5. Note that unless specifically approved in a Grading Permit issued by the Storm Water Manager, no work may be performed in the FEMA regulatory floodway without a FEMA-approved Conditional Letter of Map Revision (CLOMR).
6. An iSWM Construction Plan must be prepared by an engineer; such plan shall provide for erosion and sediment control during construction, and must be submitted as an integral part of the final engineering documents.
7. A Storm Water Pollution Prevention Plan (SWPPP) must be prepared by the engineer or another qualified professional prior to construction in accordance with TCEQ and EPA requirements. The iSWM Construction Plan submitted with the final engineering documents should normally be incorporated into the SWPPP as its erosion and sediment control plan component.
8. A Grading Permit is required prior to any construction or grading activity involving 0.1 acres or more of disturbed surface area and if disturbed surface areas are located within floodplain and/or drainage easement. A Final Grading Permit will be required prior to the issuance of a building permit. See the Final Grading Permit (Form CITY OF AZLE-10) in Appendix A for submittal information. This Final Grading Permit will be required, even if a Grading Permit was obtained at an earlier stage.
Construction Phase
1. Pre-construction Meeting - Where possible, a pre-construction meeting shall occur before any clearing or grading is initiated on the site. This step ensures that the owner-developer, contractor, engineer, and inspector can be sure that each party understands how the plan will be implemented on the site.
2. Periodic Inspections - Periodic inspections during construction by City of Azle representatives. Inspection frequency may vary with regard to site size and location; however, monthly inspections are a minimum target.
3. Final Inspection - A final inspection is needed to ensure that the construction conforms to the intent of the approved design. Prior to accepting the infrastructure components, issuing an occupancy permit, and releasing any applicable bonds, the City of Azle will ensure that: (a) temporary erosion control measures have been removed; (b) stormwater controls are unobstructed and in good working order; (c) permanent vegetative cover has been established in exposed areas; (d) any damage to natural feature protection and conservation areas has been mitigated; (e) conservation areas and buffers have been adequately marked or signed; and (f) any other applicable conditions have been met.
4. Record Drawings - Record drawings of the structural stormwater controls, drainage facilities, and other infrastructure components will be provided to the City of Azle by the developer.
5. Final Grading Certificate - (Form CITY OF AZLE-11) must be prepared by an engineer or the contractor which certifies that grading and stormwater infrastructure have been completed in substantial compliance with the Grading Permit, the iSWM Site Plan, and the SWPPP including re-vegetation and filing of Notice of Termination (NOT).
Step 5. 
Complete Operations and Maintenance Plan
An Operations and Maintenance Plan shall be developed in accordance with this section. The plan shall be included in the Final iSWM Plan. It needs to clearly state which entity has responsibility for operation and maintenance of temporary and permanent stormwater controls and drainage facilities to ensure they function properly from the time they are first installed.
The Operations and Maintenance Plan shall include but is not limited to:
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Responsible party for all tasks in the plan
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Inspection and maintenance requirements
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Maintenance of permanent stormwater controls and drainage facilities during construction
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Cleaning and repair of permanent stormwater controls and drainage facilities before transfer of ownership
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Frequency of inspections for the life of the permanent structures
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Funding source for long-term maintenance
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Description of maintenance tasks and frequency of maintenance
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Access and safety issues
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Maintenance easements
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Reviewed and approved maintenance agreements
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Testing and disposal of sediments
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Life span of structures and replacement as needed
Guidance for development of Operations and Maintenance Plans has been provided with each temporary and permanent Best Management Practice (BMP) included in the iSWM Technical Manual.
Local Provisions: A Stormwater Facility Maintenance Agreement must be prepared by the engineer for each stormwater control that will not be wholly maintained by the City of Azle. This agreement must outline both preventive maintenance tasks as well as major repairs, identify the schedule for each task, assign clear roles to affected parties, and provide a maintenance checklist to guide future owners including an annual self-inspection to be provided to the City of Azle.
For additional information, see Section 14.5.5, Stormwater Facility Maintenance Agreements.
(Ordinance 2012-10 adopted 8/21/12)