1. resourceful. naturally. Conservation Design & Volume Reduction Hanover, MN

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3. Two Project Phases 2007:Conservation Design 2009-2010: Water resource planning and regulation development –Water resource management plan –Stormwater ordinance –CD ordinance –PUD ordinance

4. resourceful. naturally. Conservation Design Project - 2007 Goals –Understand concept through concept design for actual parcel facing development –Understand key design features: Open space percentages Density Impervious surfaces –Anticipate regulations needed to support and guide CD development

5. resourceful. naturally. What is Conservation Design?

6. resourceful. naturally. What is Conservation Design?

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8. Steep Slopes & Waterways Wetlands Vegetation & Farmsteads COMPOSITE

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10. Conservation Design Scenario 1: 100 foot lots

11. resourceful. naturally. Conservation Design Scenario 2: 80 foot lots

12. resourceful. naturally. Conventional Development 2.5 Acre lots

13. resourceful. naturally. CONSERVATION DESIGN Conventional Development Scenario 1:Scenario 2: 100-Foot Frontage80-Foot Frontage Total Area 380 acres Total Buildable Area 329 acres Average Lot Size2.82 acres0.33 acres0.26 acres Lots per Acre (Buildable area)0.31 lots/acre0.88 lots/acre1.13 lots/acre Total Lots103 lots289 lots373 lots Road Miles4.6 miles6.6 miles Total Road Hard Surface19.5 acres20.8 acres Total Impervious Surface42.2 acres53.3 acres62.7 acres Percent Impervious11%14%16.5% Impervious surface/lot 0.41 acres0.16 acres0.19 acres Open Space50.5 acres211 acres210 acres Open Space Percentage of Total Area13%56% Development Analysis

14. resourceful. naturally. Water Resource Planning & Regulation Development 2009-2010 Goals –Develop stormwater performance standards Rate Volume Water quality –Performance vs. prescription –Improve standards, but balance with economic development.

15. resourceful. naturally. Planning Concerns with Infiltration Practices and Volume Control Performance Standards How will this work in different areas of the city? What is spatial impact of different volume control standards? What is reasonable balance between volume control standards and development cost?

16. resourceful. naturally. BankWest Planning Example

17. resourceful. naturally. Stormwater Performance Standards: Volume Control New Development: –Limit post development runoff volume to pre- settlement runoff volume for the 1-year storm in A and B soils. Redevelopment: –Limit post development runoff volume to pre- settlement runoff volume for the 1-year storm in A and B soils.

18. resourceful. naturally. BankWest Example: Volume Pre- settlement Existing Development Post Redevelopment (the new bank) Potential Bank Expansion Site Data Size1.61 Acre 1.61 Acres Impervious surface (area/%) 0 Acre 0% 0.42 Acre 26% 0.71 Acre 44% 1.28 Acres 80% Treatment (area/ %) N/ANone0.15 Acre 9.3% 0.15 Acre 9.3% Volume (cubic feet) No Treatment TreatmentNo Treatment Treatment 1-year event (2.4 inch) 01,9293,53207,6770 10-year event (4.2 inch) 07,88910,92787717,4494,940 100-year event (6.0 inch) 1,17115,63119,655622827,64212,700

19. resourceful. naturally. Stormwater Performance Standards: Rate Control New Development –Limit post development runoff rate to presettlement runoff rate for the 1, 10, and 100-year storm, or –0.1 cfs/acre, whichever is greater. Redevelopment –Limit post development rate to existing rate for 1, 10, and 100-year storm

20. resourceful. naturally. BankWest Example: Rate Pre- settlement Existing Development Post Redevelopment (the new bank) Potential Bank Expansion Site Data Size1.61 Acre 1.61 Acres Impervious surface (area/%) 0 Acre 0% 0.42 Acre 26% 0.71 Acre 44% 1.28 Acres 80% Treatment (area/ %) N/ANone0.15 Acre 9.3% 0.15 Acre 9.3% Rate (cfs/acre) No Treatment No Treat- ment Treatment 1-year event (2.4 inch) 00.250.8702.040 10-year event (4.2 inch) 01.242.850.124.430.87 100-year event (6.0 inch) 0.032.555.090.776.834.05

21. resourceful. naturally. Conclusions Visualizing concepts builds political support for change. –Local examples make a difference No need to regulate actual impervious surface with volume control standards. –Minimizes regulations –Increases development flexibility