BEE BRANCH WATERSHED GREEN INFRASTRUCTURE SUMMARY

Transcription

1 BEE BRANCH WATERSHED GREEN INFRASTRUCTURE SUMMARY

2 purpose & background PURPOSE & BACKGROUND Through the Bee Branch Watershed Green Infrastructure Project, the City proposes to install permeable interlocking concrete pavement at 42 different locations in the Bee Branch Watershed. When constructed, the 42 different locations will total approximately 268,000 square feet (6.2 acres) of pervious pavement for an estimated total cost of $9.42 million and result in approximately 2,400 pounds per year of TSS and 750,000 cubic feet of runoff going into the ground rather than the Mississippi River.

3 SUSTAINABLE DUBUQUE Sustainability is defined by a community s ability to meet the environmental, economic, and social equity needs of today without reducing the ability of future generations to meet their needs. Since 2006, the Dubuque Mayor and City Council have identified becoming a more Sustainable City as one of their top priorities. To that end, our City continues to implement a community-defined sustainability plan. Sustainable Dubuque is a holistic approach to making our community sustainable. Our model involves a three-part approach that addresses: Environmental and Ecological Integrity Economic Prosperity Social and Cultural Vibrancy Dubuque is a community that values Environmental Integrity Economic Prosperity Social/Cultural Vibrancy Healthy Air: fresh, clean air, reduced greenhouse gas emissions and minimized health risks. Clean Water: water as the source of life and seeks to preserve and manage it in all forms. Native Plants and Animals: biodiversity through the preservation, restoration and connection of nature and people. Regional Economy: a diversified regional economy with opportunities for new and green markets, jobs, products and services. Smart Energy Use: energy conservation and expanded use of renewable energy as a means to save money and protect the environment. Resource Management: the benefits of reducing, reusing and recycling resources. Community Design: the built environment of the past, present and future which contributes to its identity, heritage and sense of place. Green Buildings: a productive and healthy built environment. Healthy Local Foods: the benefits of wholesome food from local producers, distributors, farms, gardens and hunters. Community Knowledge: education, empowerment and engagement to achieve economic prosperity, environmental integrity and social/cultural vibrancy. Reasonable Mobility: safe, reasonable and equitable choices to access live, work and play opportunities. One of the 11 Principles to the Dubuque Model identified by Dubuque citizens is Clean Water. Sustainable Dubuque is a community that values water as a source of life and seeks to preserve and manage it in all forms. The Bee Branch Watershed Green Infrastructure Project would offer a significant and measurable improvement on water quality in the Bee Branch Creek and Mississippi River. STATE REVOLVING LOAN FUND SECONDARY FUNDING During the 2009 Iowa General Assembly session, legislation was passed to allow a new method for funding water quality protection. Senate File 339 amended the Iowa Code to add a new category of projects that can be financed with sewer revenues. This new category, called water resource restoration, includes locally directed, watershed-based projects to address water quality impairments. Before this amendment, utility revenues could only be used for construction and improvements for the wastewater system itself. With the new legislation, wastewater utilities can also finance and pay for projects, within or outside the city limits, that cover best management practices for nonpoint source pollution control. 3

4 EMPLOYMENT IMPACT The Bee Branch Green Infrastructure Project will not only improve water quality, but it will also create and preserve jobs. Following guidance by the US DOT, a project the size of the Bee Branch Green Infrastructure Project will create or preserve approximately 102 jobs over the three year project life. CITY COUNCIL SUPPORT The City Manager will present a resolution to the City Council at their February 20, 2012 regular meeting. If approved as anticipated, a copy of the resolution will be attached to this document as Exhibit A for the meeting with Iowa DNR and IFA on February 22, 2012.

5 summary The Bee Branch Watershed covers approximately 6.5 square miles of the City of Dubuque and is almost fully developed. PROPOSAL SUMMARY Following an intense thunderstorm in 1999, the City of Dubuque commissioned an engineering study and the development of the Drainage Basin Master Plan (DBMP). In addition to identifying at-risk properties, the DBMP identified three major projects to provide flood control and water quality improvement: the Carter Road Detention Basin; the expansion and improvement of the 32nd Street Detention Basin; and the restoration of the Bee Branch Creek. The City has completed the first two projects, and the Bee Branch Creek Restoration Project is currently under construction. For the most part, these projects address stormwater management on a regional scale after runoff has already been increased due to development. With the Bee Branch Watershed Green Infrastructure Project, the City of Dubuque proposes to take stormwater management a step further by managing it at the site, when rainfall hits the ground. The Bee Branch Watershed Green Infrastructure Project includes over six acres in permeable paver alleys and parking lots which will result in preventing almost 2,400 pounds of sediment and 750,000 cubic feet of runoff per year from entering the Mississippi River. BEE BRANCH CREEK RESTORATION PROJECT BACKGROUND In May 1999, many Dubuque residents living in the 6.5-square mile Bee Branch Watershed (Figure 1) experienced heavy rains that resulted in significant basement flooding and costly furnace and foundation repairs. Unfortunately, that scenario repeated itself in 2002, 2004, 2010 and 2011 as heavy rainfall over the watershed caused flooding in more than 1,100 homes and businesses. Among the causes were the frequent and intense rainfall events, uncontrolled development from over 30 years ago, and an undersized storm sewer system. Therefore, the City initiated the Bee Branch Creek Restoration Project to replace almost one-mile of storm sewer with a creek and floodplain that resembles the one that traversed the area approximately 100 years ago. The design of the restored creek meanders through a 15 to 25-foot wide flood management corridor. The location of the project will extend 4,500 feet from the 16th Street Detention Basin north to Comiskey Park at 24th and Elm Streets. This open waterway system will transition former industrial use to commercial land-use that is compatible in nature with the adjacent residential areas. The project was designed through a highly interactive citizen engagement process and includes many amenities that enhance the existing low income neighborhoods while providing a model to address stormwater management and water quality. RESTORATION PROJECT INCLUDES: Daylighting 4,500 feet of buried creek; Restoring creek and associated floodplain; Lower Bee Branch overlook, floating bioisland, rain gardens and bioswales; Creating a linear park along the open waterway; Amphitheater adjacent to an elementary school to provide opportunities for outdoor education; Recreation bike/hike trails that connect to the urban bike system and to the regional trails; and Planting of over 1,000 trees, neighborhood fruit orchards, and community garden space. 5

6 RESTORATION PROJECT BENEFITS: Reduces flood risk for over 1,100 homes and businesses; Integrates land management, historic preservation, natural preservation, and watershed management in an urban area; Creates a local amenity and tourist attraction through a community engagement process; and Supports 7 of 11 City Sustainability Principles Figure 1. Bee Branch Watershed and location of the Bee Branch Restoration Project 6

7 GREEN INFRASTRUCTURE Green Infrastructure is an approach to stormwater management that is cost-effective, sustainable, and environmentally friendly. Green Infrastructure management approaches and technologies infiltrate, evapotranspire, capture and reuse stormwater to maintain or restore natural hydrology. At the largest scale, the preservation and restoration of natural landscape features (such as forests, floodplains and wetlands) are critical components of green stormwater infrastructure. On a smaller scale, green infrastructure practices include rain gardens, porous pavements, green roofs, infiltration planters, trees and tree boxes, and rainwater harvesting for non-potable uses such as toilet flushing and landscape irrigation. Figure 2 shows a green alley constructed in Dubuque as part of a 2010 pilot project. PERMEABLE INTERLOCKING PAVERS Figure 2. Green alley pilot project in Dubuque. The Iowa Stormwater Manual differentiates porous pavement into three different types: pervious concrete pavement; porous asphalt pavement; and permeable interlocking concrete pavers (PICP). A typical detail of PICP design is provided in Figure 3. Regardless of the material, the stormwater management principle is generally the same for each pavement: openings in the pavement surface allow rainfall and runoff to be quickly transferred below the pavement into rapidly infiltrating soils or into a rock storage bed. The rock storage bed then acts as an underground pond that holds water and allows it to infiltrate back into the ground. Figure 3. Typical detail of a permeable interlocking concrete pavement (PICP) 7

8 GREEN ALLEY PROJECT LOCATION, SCHEDULE AND COST Through the Bee Branch Watershed Green Infrastructure Project, the City proposes to install permeable interlocking concrete pavement at 42 different locations in the Bee Branch Watershed. Approximately 40 will be green alleys for a total area of approximately 219,000 square feet at an estimated cost of $8.75 million. Two installations are proposed in parking lots over an area of approximately 49,000 square feet at an estimated cost of $663,000. When constructed, the 42 different locations will total approximately 268,000 square feet (6.2 acres) of pervious pavement for an estimated total cost of $9.42 million. The City proposes to implement the project over three years. Table 1 outlines the annual schedule and budget for constructing alleys and/or parking lots in 2012, 2013, and Table 1. Summary of proposed schedule and budget Year Surface Area (sq ft) Cost 2012 Alleys 69,776 $2,891,300 Parking Lots 0 $ Alleys 87,376 $3,316,400 Parking Lots 49,315 $663, Alleys 61,440 $2,545,882 Parking Lots 0 $0 TOTAL 267,907 $9,416,795 To date, the City has converted four standard alleys to pervious, which is approximately 1% of all alleys in the Bee Branch Watershed. This percentage would increase to almost 20% upon completion of the Bee Branch Watershed Green Infrastructure Project. City staff estimate that approximately $35 million is necessary to convert all alleys to pervious surface. 8

9 water quality benefits WATER QUALITY BENEFITS The greatest benefit of pervious pavement is that it allows water to go back into the ground where it went prior to development. Although sometimes more costly than other Green Infrastructure practices, pervious pavement is typically the most efficient at removing pollutants from runoff because the pollutants are allowed to go back into the ground rather conveyed to another practice that requires regular maintenance to remove the collected pollutants. City of Dubuque staff used the computer models WinSLAMM and P8 to simulate the water quality benefit of the proposed Bee Branch Watershed Green Infrastructure Project. P8 was used to determine the expected pollutant loading and runoff volume, while WinSLAMM was used to determine the pollutant removal and volume abstraction percentages. WinSLAMM was chosen for the removal percentages because it includes a specific calculation routine for pervious pavement, and it is based on actual field observations, with minimal reliance on theoretical processes that have not been adequately documented or confirmed in the field. The models predict that the Bee Branch Watershed Green Infrastructure Project could reduce total suspended solids (TSS) loading to the Mississippi River by approximately 67% and runoff volume by approximately 50%. When fully constructed, this project will result in approximately 2,400 pounds per year of TSS and 750,000 cubic feet of runoff going into the ground rather than the Mississippi River. The EPA Fact Sheet Permeable Interlocking Concrete Pavement supports these results by reporting a reduction in TSS of 67-81% and a 34-66% reduction in runoff volume for designs with an underdrain. 9

10 EXISTING STATE REVOLVING FUND LOAN The City of Dubuque and the Iowa Housing Authority entered into a State Revolving Fund Loan agreement in the amount of $64,885,000 on August 18, 2010 to upgrade the City s wastewater treatment plant. Terms of the loan include a one-time 1% initiation fee of $648,850, 3% annual interest rate, and a 0.25% annual administration fee. The administration fee is based on the requested loan amount until disbursements are finalized and then the administration fee is assessed against the outstanding balance as of June 1 each year. The loan will be paid over 26 years with semi-annual interest payments due June 1 and December 1, and an annual principal payment due June 1. Principal payments begin June 1 after the final loan distribution. It is estimated that the first principal payment will be made June 1, Semi-annual interest payments will be made during the construction period. A summary of the loan terms is provided in Table 2. As of February 10, 2012, the City has received $38,043,784 in loan disbursements, including the roll in of $95,500 from the Plant Study Loan and $3,200,000 from the Planning and Design Loan. Total disbursements plus loan initiation fee equals $38,692,634. Total interest paid is $1,368,750 and is listed in Table 3. Per the DNR guidance document for sponsored project applications, the City proposes that the August 2010 SRF loan and related loan application be amended to allow the City to use a portion of the interest to pay costs of the Bee Branch Watershed Green Infrastructure Project (Project). The City expects to enter into a separate construction contract for the Project and to request Project-related disbursements at the same time it makes requests for disbursements for Wastewater Treatment Plant costs under the existing loan. Figure 4. Aerial view of wastewater treatment plant prior to construction. Table 2. Loan summary Loan Closing Date August 18, 2010 Final Maturity Date June 1, 2039 Loan Period in Years 26 Total Loan Amount Requested $64,885, Less: 1% Initiation Fee $648, Net Proceeds to Borrower $64,236, Annual Interest Rate 3.00% Total Interest $33,201, Servicing Fee Rate 0.25% Total Servicing Fees $2,965, Total Loan Costs $36,815, Table 3. Total interest paid on loan as of February 10, Date Initiation Annual Semi-Annual Total Fee Administration Fee Interest 8/18/2010 $648, $648, /1/ $37, $37, /1/ $162, $158, $321, /1/ $361, $361, TOTAL $648, $162, $557, $1,368,

11 EXISTING 28E AGREEMENT The adoption of Iowa Code Chapter 28E in 1965 provided political subdivisions with a great expansion of their authority for intergovernmental cooperation. The essence of this legislation was to permit any governmental agency to undertake any activity jointly with any other agency so long as each agency has the power to undertake that particular activity on its own. As an example, since cities, townships, counties, and schools can establish libraries, it became possible for a library to be a joint undertaking by a combination of these types of local governments. The City of Dubuque and Dubuque County currently have a 28E agreement in place for an urban conservation program. The agreement created an urban conservationist position to perform urban conservation and watershed related activities pertinent to Dubuque County, the City of Dubuque, and the Dubuque Soil & Water Conservation District. Among others, the Urban Conservationist responsibilities include: Participating in any educational/outreach programs in accordance with the City s NPDES permit and stormwater/ watershed program. Providing technical assistance for any urban conservation activities, including, in-field assessment, design, and public/ private projects. Continuing a strong connection with the City s sustainability efforts, building upon needs and necessary improvements. The City is in the process of creating a new 28E agreement for the SRF sponsored project option. A draft of the new 28E agreement is attached as Exhibit B. FOR MORE INFORMATION: Lead point of contact for the City of Dubuque: Teri Goodmann Assistant City Manager City of Dubuque 50 West 13th Street Dubuque, Iowa tgoodman@cityofdubuque.org Assisting with the project, all communications should copy: David Lyons Smarter Sustainable Dubuque Project Manager dlyons@cityofdubuque.org S M A R T E R 11