Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting April 18, 2018

Agenda

• Water quality and green infrastructure • Overview: Marion Street stormwater project • Green infrastructure opportunity

• Overview • Table exercise: Getting to know Marion St

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

The Problem

Over 1200 Total Outfalls • 300+ Outfalls into Cherry Creek

• 300+ Outfalls into South Platte

13% of Denver’s 98,900+ acres receive water quality treatment 2013 Matrix Report

Denver’s Streams:

0/10 meet recreation standards

7/10 suitable for aquatic life 2016 Water Quality Report, Denver Dept. of Environmental Health

Addressing These Challenges

Grey Infrastructure

Community Strategic Green Engagement Infrastructure Planning

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Green Infrastructure • Natural or built systems that use

vegetation and soils to manage stormwater runoff

• More resilient approach than relying ongray alone

• Numerous benefits

• Varying scales Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Benefits of Green Infrastructure

•

•

•

•

• Improve water quality

• Reduce flood risks

• Reduce Urban Heat Island effect

• Improve air quality

• Absorb local carbon emissions

• Improve public health outcomes Increase physical activity

Improve mental wellbeing

Reduce stress

Lower traffic speeds and reduce injury

crashes

• Improve property values

Sub/Regional Scale Green Infrastructure

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Site-Scale Green Infrastructure

Cur

rent

Pr

ojec

ts

33rd Street Outfall Brighton Boulevard

Hampden Heights Carla Madison Recreation Center 21st and Broadway

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

16t Street (Upper Montclair Basin)

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Denver’s Residential Green Infrastructure

Lowell and Evans

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Green Infrastructure and Health 2017 – Denver Department of Public Health and Environment produced white paper about green infrastructure and potential health risks.

Key findings: Concern Finding Organic Compound Low levels, not a concern to public health (compared to EPA health risk guidelines) Heavy Metals Low levels, not a concern to public health (compared to EPA health risk guidelines) Bacteria and Human Pathogens Public health risk no greater than exposure to other sediments and soils Nitrogen and Phosphorous Nitrogen generally not retained in sediments; phosphorous generally in insoluble, mineralized

form

Disease Carrying Vectors Facilities are designed to drain quickly in order to eliminate or minimize mosquito habitat

For full copy of white paper, please email: waterquality@denvergov.org

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Maintenance

• Soft • Trash collection and sediment removal:

• City Maintenance Contract • Vegetation:

• City Maintenance Contract • BID/MID • Neighborhood Stewards

• Hard = Concrete and pipe structures • Denver Public Works

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

STORM DRAIN IMPROVEMENTS – THE BIG PICTURE

The 33rd Street Outfall and the Marion Street System are key components for upgrading the level of drainage service within the neighborhoods of Five Points, Cole, Whittier, and City Park West. The new storm drain system will improve drainage during a five-year storm event and address areas where significant flooding could occur

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

33RD STREET OUTFALL PROJECT

Three of the four segments have already been constructed. Construction for the fourth and final segment, which runs from Curtis Street to Marion Street just south of Martin Luther King Jr Boulevard, is anticipated to begin in the summer of 2018

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

33RD STREET OUTFALL STRUCTURE

The new outfall structure at the South Platte River was designed to connect to the river overbank rather than to the river itself, facilitating stormwater treatment prior to entering the river

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

STORM DRAIN CAPACITY – EXISTING VS. PROPOSED

The new storm drain in 33rd Street is approximately 28 times larger than the existing 24"-diameter storm drain

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

33RD STREET OUTFALL – NEW STORM DRAIN

A photo of the 33rd Street Outfall System under construction - note the shovel and broom inside the pipe, and the workers standing above

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

FLO-2D ANALYSIS (EXISTING CONDITIONS)

A model of the estimated maximum flow depths for the 100-year storm (that is, on average, one would expect a storm of this intensity or greater to occur only once in 100 years) prior to the construction of the 33rd Street Outfall

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

FLO-2D ANALYSIS (PROPOSED CONDITIONS)

A model of the estimated maximum flow depths for the 100-year storm (that is, on average, one would expect a storm of this intensity or greater to occur only once in 100 years) after the construction of the 33rd Street Outfall

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

100-YEAR STORM DEPTH REDUCTIONS

The 33rd Street Outfall System will alleviate (relatively) frequent flooding problems in the Five Points/Whittier/Cole neighborhoods; however, benefits can also be expected for larger, less frequent storms, as well. Note the depth reductions in the figure to the right for the 100-year storm (that is, on average, one would expect a storm of this intensity or greater to occur only once in 100 years)

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

33RD STREET OUTFALL PROJECT – ADDITIONAL INFORMATION

Visit the City’s website to view overall project status, photos, videos, and to sign up for project updates. Simply type “Denver 33rd Street Outfall” in your search engine of choice, or search for the project at www.denvergov.org

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

MARION STREET SYSTEM

The Marion Street System is a key component for upgrading the level of drainage service within the Whittier neighborhood (projects "A" and “B" in the master plan map, right). The new pipe in Marion Street will intercept storm drain laterals to the east (21st through 31st Avenues), and will form a "dual system" with the existing storm drain in Downing Street that will continue to convey runoff from nearly all of the City Park West and Cheesman Park neighborhoods

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

PHASES, SCHEDULE & IMPACTS

The project will be split in two phases - from Martin Luther King Jr Boulevard to 26th Avenue (Phase I) and from 26th Avenue to the 21st Avenue and Downing Street intersection (Phase II)

Phase I is anticipated to begin in summer 2019; Phase II in the early part of 2020

General neighborhood impacts include temporary street closures with loss of on-street parking, one block at a time

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

SURFACE DRAINAGE IMPROVEMENTS

Drainage conditions at each intersection along the Marion Street corridor will be significantly improved. For instance, new drainage inlets will be placed upstream of pedestrian curb ramps, as shown in this excerpt from the City's Storm Drainage Design & Technical Criteria Manual

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

STORM DRAIN CAPACITY – EXISTING VS. PROPOSED

By retaining the existing storm drain in Downing Street and constructing a parallel storm drain in Marion Street, the capacity of the drainage system will increase fourfold, as illustrated here

Opportunity:Green Infrastructure on Marion Street • Implement GI on Marion Street as part of pipe project • Cost-efficient

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Marion Street Green Infrastructure Project Whittier Neighborhood Community Meeting | April 18, 2018

Activity: What does Marion look like?

• Residents interested in green infrastructure Phase 1: • Intersection patterns MLK to 26th Street • Parking needs • Other issues in the neighborhood