Volume 2-05, Chapter 3 - City of Wichita
Volume 2-05, Chapter 3 - City of Wichita Volume 2-05, Chapter 3 - City of Wichita
Section 3.1 - Stormwater Management Controls Overview Structural Controls on Each Development Site Regional Structural Stormwater Control Figure 3-5 On-Site vs Regional Stormwater Management 3.1.5.2 Advantages and Disadvantages of Regional Stormwater Controls The use of a regional stormwater facility is not always the best solution and the following “pros” and “cons” should be considered during the decision process. Advantages of Regional Stormwater Controls Reduced Construction Costs: Design and construction of a single regional stormwater control facility can be more cost-effective than numerous individual on-site structural controls. Reduced Operation and Maintenance Costs: Rather than multiple owners and associations being responsible for the maintenance of several stormwater facilities on their developments, it is simpler and more cost effective to establish scheduled maintenance of a single regional facility. Higher Assurance of Maintenance: Regional stormwater facilities are far more likely to be adequately maintained as they are large and have a higher visibility. Maximum Utilization of Developable Land: Developers would be able to maximize the utilization of the proposed development for the purpose intended by minimizing the land normally set aside for the construction of stormwater structural controls. Other Benefits: Well-sited regional stormwater facilities often can serve as a community recreational and aesthetic amenity. Disadvantages of Regional Stormwater Controls Location and Siting: Regional stormwater facilities may be difficult to site, particularly for large facilities or in areas with existing development. Maintenance: The local government is typically responsible for the operation and maintenance of a regional stormwater facility. Page 3 - 18 Volume 2, Technical Guidance
Section 3.1 - Stormwater Management Controls Overview Need for Planning: The implementation of regional stormwater controls requires substantial planning, financing, and permitting. Land acquisition must be in place ahead of future projected growth. Water Quality and Channel Protection: Without on-site water quality and channel protection, regional controls do not protect smaller streams upstream of the facility from degradation and channel erosion. Ponding Impacts: Upstream inundation from a regional facility impoundment can eliminate floodplains, wetlands, and other habitat. 3.1.5.3 Important Considerations for the Use of Regional Stormwater Controls If a regional stormwater control is planned, then it must be ensured that the conveyances between the individual upstream developments and the regional facility can handle the design peak flows and volumes without causing adverse impact or property damage. Siting and designing regional facilities may be done by city of Wichita and/or Sedgwick County as part of watershed master planning efforts. Development and redevelopments will be required to compensate the local jurisdiction for construction of these regional facilities through any equitable and legal system proposed in the watershed master plan. At a minimum, future watershed master plans must provide: • Protection against water quality impacts to meet the 80% TSS removal standard; • protection against channel erosion to meet the channel protection requirement; and, • protection against downstream flooding to meet the peak flow control standard and 10% rule. Furthermore, unless the system consists of completely man-made conveyances (i.e. storm drains, pipes, constructed channels, etc) on-site structural controls for water quality and downstream channel protection will likely be required for all developments within the regional facility’s drainage area. Federal water quality provisions do not allow the degradation of water bodies from untreated stormwater discharges, and it is U.S. EPA policy to not allow regional stormwater controls that would degrade stream quality between the upstream development and the regional facility. Further, without adequate channel protection, aquatic habitats and water quality in the channel network upstream of a regional facility may be degraded by channel erosion if they are not protected from bankfull flows and high velocities. Based on these concerns, both the EPA and the U.S. Army Corps of Engineers have expressed opposition to in-stream regional stormwater control facilities. In-stream facilities should be avoided if possible and will likely need to be permitted on a case-by-case basis. Volume 2, Technical Guidance Page 3 - 19
- Page 1 and 2: CHAPTER 3 STORMWATER CONTROLS TABLE
- Page 3 and 4: Chapter 3 - Table of Contents 3.2.8
- Page 5 and 6: Chapter 3 - Table of Contents LIST
- Page 7 and 8: Section 3.1 - Stormwater Management
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- Page 31 and 32: Section 3.2.1 - Stormwater Pond 3.2
- Page 33 and 34: Section 3.2.1 - Stormwater Pond Fig
- Page 35 and 36: Section 3.2.1 - Stormwater Pond For
- Page 37 and 38: Section 3.2.1 - Stormwater Pond •
- Page 39 and 40: Section 3.2.1 - Stormwater Pond 1'
- Page 41 and 42: Section 3.2.1 - Stormwater Pond •
- Page 43 and 44: Section 3.2.1 - Stormwater Pond •
- Page 45 and 46: Section 3.2.1 - Stormwater Pond 3.2
- Page 47 and 48: Section 3.2.1 - Stormwater Pond Ste
- Page 49 and 50: Section 3.2.1 - Stormwater Pond Fig
- Page 51 and 52: Section 3.2.1 - Stormwater Pond Fig
- Page 53 and 54: Section 3.2.2 - Extended Dry Detent
- Page 55 and 56: Section 3.2.2 - Extended Dry Detent
- Page 57 and 58: Section 3.2.2 - Extended Dry Detent
- Page 59 and 60: Section 3.2.3 - Vegetative Filter S
- Page 61 and 62: Section 3.2.3 - Vegetative Filter S
- Page 63 and 64: Section 3.2.3 - Vegetative Filter S
- Page 65 and 66: Section 3.2.3 - Vegetative Filter S
- Page 67 and 68: Section 3.2.4 - Grassed Channel 3.2
- Page 69 and 70: Section 3.2.4 - Grassed Channel 3.2
- Page 71 and 72: Section 3.2.4 - Grassed Channel 3.2
- Page 73 and 74: Section 3.2.4 - Grassed Channel max
Section 3.1 - Stormwater Management Controls Overview<br />
Structural Controls on Each<br />
Development Site<br />
Regional Structural<br />
Stormwater Control<br />
Figure 3-5 On-Site vs Regional Stormwater Management<br />
3.1.5.2 Advantages and Disadvantages <strong>of</strong> Regional Stormwater Controls<br />
The use <strong>of</strong> a regional stormwater facility is not always the best solution and the following<br />
“pros” and “cons” should be considered during the decision process.<br />
Advantages <strong>of</strong> Regional Stormwater Controls<br />
Reduced Construction Costs: Design and construction <strong>of</strong> a single regional stormwater control<br />
facility can be more cost-effective than numerous individual on-site structural controls.<br />
Reduced Operation and Maintenance Costs: Rather than multiple owners and associations<br />
being responsible for the maintenance <strong>of</strong> several stormwater facilities on their developments,<br />
it is simpler and more cost effective to establish scheduled maintenance <strong>of</strong> a single regional<br />
facility.<br />
Higher Assurance <strong>of</strong> Maintenance: Regional stormwater facilities are far more likely to be<br />
adequately maintained as they are large and have a higher visibility.<br />
Maximum Utilization <strong>of</strong> Developable Land: Developers would be able to maximize the<br />
utilization <strong>of</strong> the proposed development for the purpose intended by minimizing the land<br />
normally set aside for the construction <strong>of</strong> stormwater structural controls.<br />
Other Benefits: Well-sited regional stormwater facilities <strong>of</strong>ten can serve as a community<br />
recreational and aesthetic amenity.<br />
Disadvantages <strong>of</strong> Regional Stormwater Controls<br />
Location and Siting: Regional stormwater facilities may be difficult to site, particularly for large<br />
facilities or in areas with existing development.<br />
Maintenance: The local government is typically responsible for the operation and<br />
maintenance <strong>of</strong> a regional stormwater facility.<br />
Page 3 - 18<br />
<strong>Volume</strong> 2, Technical Guidance
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