Mobley, Palencia

Palencia Mobley, P.E. was appointed as the Deputy Director and Chief Engineer of the Detroit Water and Sewerage Department by Mayor Mike Duggan and approved by the Board of Water Commissioners in January 2016. She is currently responsible for the engineering, facilities, capital construction and regulatory affairs of the department. Mobley is a graduate of the University of Michigan with a Bachelor of Science in Chemical Engineering and Wayne State University with a Master of Science in Civil and Environmental Engineering.

Titles from this speaker

Detroit's Learning Curve with New Stormwater Regulations

Abstract

During the first year of Detroit’s stormwater regulations, it was made very clear how important it is to create laws with a triple bottom line approach, encouraging economic growth, while aggressively working towards the goal of eliminating combined sewer overflows. Shifting developers focus to now include dedicated space to manage stormwater has allowed the opportunity for, planners, designers, developers, and city engineers to work together and identify Detroit-specific best management practices. As part of compliance with the Detroit Water and Sewerage Department’s National Pollutant Discharge Elimination System (NPDES) Permit, the City of Detroit passed its first Post-Construction Stormwater Management Ordinance (PCSWMO) in November 2018. Up until the passage of Detroit’s stormwater regulations, developers in Detroit had no obligation to manage stormwater and instead directed runoff into the combined sewer system. Shifting developers focus to now include dedicated space to manage stormwater has allowed the opportunity for, designers, developers, and DWSD engineers to work together and identify if there is room for improvement based upon existing site conditions.

SpeakerMobley, Palencia

Presentation time

08:30:00

08:50:00

Session time

08:30:00

09:30:00

SessionStormwater Rules! Making Codes and Ordinances Work for You

Session number316

TopicPolicy and Regulation, Stormwater, Green Infrastructure, and Wet Weather, Utility Management and Leadership

Author(s)

P. MobleyS. StoolmillerL. Wallick

Author(s)P. Mobley1; S. Stoolmiller1; L. Wallick2;

Author affiliation(s)City of Detroit Water and Sewerage Department1; Detroit Wastewater Partners 2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157876

Volume / Issue

Content sourceWEFTEC

Word count8

Flood Control and Water Quality: Balancing Gray and Green Infrastructure in Detroit

Abstract

The Detroit Water and Sewerage Department (DWSD) has completed the design of a $25 million project to reduce flows to the City's combined sewer system, thereby having a major impact on a nearby combined sewer overflow (CSO) that currently discharging to the adjacent Rouge River during most wet weather events. The project includes a near-complete sewer separation within a 214-acre residential neighborhood on the far west side of the City of Detroit. The project is known as the Far West Detroit Stormwater Improvements Project ('Far West'). Key Learning Objectives: 1. Highlight the benefits of using adjacent park lands to install a large scale naturalized extended detention feature that provides water quantity and quality benefits beyond sewer separation. 2. Summarize a methodology to demonstrate how the design meets water quality (TSS reduction) objectives. 3. Demonstrate how a regional sewer model can be used to evaluate project impacts. 4. Discuss the establishment of a pre- and post-construction flow metering program to quantify the impacts of the project. A large park (Rouge Park) is adjacent to the residential neighborhood which provided a unique opportunity to include Green Stormwater Infrastructure (GSI) design components (see Figures 1 and 2). The design consisted of a linear extended detention conveyance channel that incorporates native plantings, floodplain benches, and plunge pools (Figures 1 & 2). This will allow for treatment and flow attenuation of stormwater runoff prior to discharge to the Rouge River, an impaired waterway draining one of the nations' oldest and most industrialized watersheds. Water quantity was addressed in the design through a conveyance channel at the proposed separate storm sewer outfalls from the Far West neighborhood. This conveyance channel provides ample storage volume for both frequent and infrequent hydrologic events, with a focus on extended detention for smaller storms, up to the 2-year recurrence interval. The channel was also designed to be a natural feature that would enhance Rouge Park, and the design includes the establishment of a pedestrian pathway to allow area residents to walk along the edge of the channel. Natural, native vegetation along the channel banks will discourage people from climbing into the channel and will provide additional water quality benefits through erosion protection and nutrient uptake. To quantify the potential TSS removal of the open channel, the calculation procedure for sizing sediment containment systems described in the State of Florida Erosion and Sedimentation Control Designer and Reviewer Manual (2013) was used. This procedure uses a design soil particle size and calculates the apparent removal effectiveness of design size (and larger) particles suspended in runoff waters using the settling velocity from Stokes' Law, design flow rates and sediment containment geometry. The design soil particle size for this assessment is 75 microns based on a geotechnical report that provided a grain size distribution for three boring locations where the samples were collected within the top 12 inches of the soil surface. Finally, two storm events, the Water Quality Event (1-inch) with a one-hour duration and the Channel Protection Event (2-yr 24-hr), were modeled in SWMM and HEC-RAS to provide the hydrology and hydraulics of the channel for sediment transport calculations (Figure 3). For the Water Quality Event, the calculated TSS effectiveness of both channels for the 75-micron size is 100% and the net effectiveness of all suspended particles is 82%. For the Channel Protection Event, the apparent effectiveness of the north channel for the 75-micron size is 100% and for the south channel it is 97%. The net effectiveness of all suspended particles is 82% for the north channel and 80% for the south channel. This approach for calculating TSS removal met with regulatory approval which mandates a 80% TSS removal rate. Water quality impacts to the Rouge River extend beyond the GSI components of this project. The partial separation of a 214-acre neighborhood will have a profound impact on the frequency and volume of CSOs at the Rouge River. The Great Lakes Water Authority (GLWA) developed a regional SWMM model of the collection system tributary to their Water Resource Recovery Facility, and this SWMM model was used to evaluate the impacts of the Far West project. The modeling effort revealed that this project, in concert with related hydraulic improvements downstream of the CSO, will decrease the CSO frequency to once in ten years. The 10-year recurrence interval peak flow in the combined sewer, upstream of the CSO, will be reduced by approximately 200 cfs. In addition to system modeling, pre- and post-construction flow metering is being conducted within the project area. A flow meter was installed on an existing 72-inch combined sewer at the downstream end of the Far West project area and a rain gage was also installed on area neighborhood school roof. On June 25-26, 2021, metro Detroit was hit with a large rainfall event causing regionwide flooding. The Far West rain gage measured 5.0 inches of rainfall in a 24-hour period; fortunately, the flow data from this event looked very reliable and serves as a useful design storm benchmark against which post-construction conditions can be compared. Preliminary modeling of this event demonstrates that the proposed system will function without surface flooding and with a considerable reduction in CSO volume. This project balances sewer separation and CSO flow/volume reduction with additional treatment of surface water. This enhances the water quality in the Rouge River in two ways: 1) enhanced water quality through CSO volume reduction, and 2) extended detention of separated stormwater, reducing TSS loading and peak flows to the Rouge River. Furthermore, DWSD is able to meet the commitments in their CSO NPDES Permit through the implementation of GSI. The project has been bid and the construction contract award is expected in late 2021, with construction commencing in early 2022 and ending in 2026.

This paper was presented at the WEF Collection Systems Conference in Detroit, Michigan, April 19-22.

SpeakerMobley, Palencia

Presentation time

8:30:00

9:00:00

Session time

8:30:00

11:15:00

Session number15

Session locationHuntington Place, Detroit, Michigan

TopicCombined Sewer Overflow, Green Infrastructure, Modeling

Author(s)

H. Jahangiri

Author(s)H. Jahangiri1; D. Carpenter2; G. Kacvinsky3; P. Mobley4; L. Wallick5; S. Stoolmiller6

Author affiliation(s)WEF Member Account1; WEF Member Account2; WEF Member Account3; Detroit Water and Sewerage Dept4; Detroit Water and Sewerage Dept5; Detroit Water and Sewerage Dept6

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Apr, 2022

DOI10.2175/193864718825158371

Volume / Issue

Content sourceCollection Systems

Word count13

Description: Public-Private Partnership Developed Website and Mapping Tool Promoting Green...

Public-Private Partnership Developed Website and Mapping Tool Promoting Green Stormwater Infrastructure in Detroit

Abstract

Public and private organizations across the City of Detroit have teamed up to promote Green Stormwater Infrastructure. With continuous collaboration, the Detroit Stormwater Hub was launched as a place to learn, share, and track green stormwater projects across Detroit.

SpeakerMobley, Palencia

Presentation time

10:50:00

11:10:00

Session time

10:30:00

11:30:00

Session#StormwaterData: Using Technology to Inform Program Decisions

Session number317

TopicIntelligent Water, Stormwater, Green Infrastructure, and Wet Weather

Author(s)

P. MobleyL. WallickJ. Moore

Author(s)P. Mobley1; L. Wallick2; J. Moore1;

Author affiliation(s)City of Detroit Water and Sewerage Department, MI1; Detroit Wastewater Partners, MI2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157892

Volume / Issue

Content sourceWEFTEC

Word count14

Public Support for Private Green Stormwater Infrastructure in Detroit, MI

Abstract

The Detroit Water and Sewerage Department has multiple new programs to foster and incentivize private GSI installation in the city. Through operation of these programs, DWSD has learned many lessons that are applicable to municipalities across the US, North America and the rest of the world.

SpeakerMobley, Palencia

Presentation time

15:50:00

16:10:00

Session time

15:30:00

16:10:00

SessionA Tale of Three Cities: Green Infrastructure Incentives in Urban Areas

Session number420

TopicPolicy and Regulation, Stormwater, Green Infrastructure, and Wet Weather, Utility Management and Leadership

Author(s)

P. MobleyL. WallickR. GibsonE. Falkner

Author(s)P. Mobley1; L. Wallick2; R. Gibson1; E. Falkner1;

Author affiliation(s)City of Detroit Water and Sewerage Department, MI1; Detroit Wastewater Partners, MI2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157433

Volume / Issue

Content sourceWEFTEC

Word count11

Description: Using AI(Artificial Intelligence) to Measure IA(Impervious Acreage) In a Rapidly...

Using AI(Artificial Intelligence) to Measure IA(Impervious Acreage) In a Rapidly Changing Landscape

Abstract

Improving DWSD’s workflows from manually derived data to machine learning derived data delivered annually allows DWSD to keep departmental metrics current. With the City of Detroit experiencing so much change, this new process will aid decision makers in understanding how and where the landscape is shifting. The accuracy of this data allows decision makers to share information across multiple agencies and have confidence regarding land use and economic development.

SpeakerMobley, Palencia

Presentation time

14:10:00

14:30:00

Session time

13:30:00

15:10:00

SessionTowards the Digital Sewershed: What's In Yours?

Session number224

TopicAsset Management, Facility Operations and Maintenance, Intelligent Water, Utility Management and Leadership

Author(s)

A. StuyvesantP. MobleyL. WallickM. McCloskey