THE LIFE-CYCLE COSTS AND BENEFITS OF RAIN GARDENS IN MINNESOTA

1. THE LIFE-CYCLE COSTS AND BENEFITS OF RAIN GARDENS IN MINNESOTA Chris Hartzell & Joe Nietfeld

2. INTRODUCTION • Rain Gardens ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

3. RELEVANCE • Minnesota • Push from communities and watershed management organizations to utilize rain water gardens • Incomplete or incomprehensible studies have been done so far regarding rain water gardens • Development • Cities are encouraging developers to utilize rain gardens versus traditional storm sewer through the use of an incentive • Cities need to quantify benefit to their community ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

4. ADVANTAGES • Advantage of Rain Gardens • Cheaper to build versus traditional storm water conveyance methods • Greater beauty with a well maintained garden • Recharges groundwater locally • Takes pollutants out of storm water runoff • Return to pre-development hydrology ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

5. DISADVANTAGES • Disadvantage of Rain Gardens • Poor construction methods allow mosquitoes to breed • City or resident does not follow through on maintenance activities • Necessity for more land • Loss of land value • Only handle small storm water runoff events • They don’t provide flood control • Bio-retention is started after homes are built • Long-term benefits have not been studied ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

6. PROBLEM STATEMENT • Since rain gardens are a relatively new concept, little is known about their long-term maintenance costs relative to traditional storm water management practices ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

7. PROBLEM STATEMENT • Infrastructure Systems Engineering (ISE) practices such as life cycle cost and cost benefit analysis could be applied to rain gardens to evaluate them over their entire life from design to construction to long term maintenance ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

8. OBJECTIVE • Evaluate the effectiveness of rain gardens over their life cycles relative to a traditional storm water management system ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

9. COSTS AND BENEFITS • Life Cycle Costs • Design • Construction • Quality Control • Long Term Maintenance • Benefits • Pollutant Removal • Storm water reduction ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

10. PARAMETERS AFFECTING COST • Soil Conditions • Hydrology • Location • Infiltration Rates • Plant Species • Land Prices ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

11. EXPECTED PRODUCT “ A detailed “Best Uses” Guide showing the most effective uses of rain gardens from a life cycle perspective • To be used as a… • Storm Water Management Tool • Municipalities • Developers • Decision Making Tool • Will rain gardens work in the community • Determine incentives to give to developers ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller

12. QUESTIONS? ISE 8105: Capstone Design Infrastructure Systems Engineering Instructor: Vaughn Voller