Nickel, Tristan, Nickel

Nickel, Tristan

Mr. Nickel started his career working in the field with inspection crews conducting a variety of different condition assessment activities. While he has been involved in a wide array of projects for various municipalities in his 17 years of experience sewer inspection has always been at the forefront of his career. He has project experience ranging from condition assessment, hydraulic capacity analysis, rehabilitation design, and construction management of sanitary sewer systems. He has managed projects that focused on inflow and infiltration reduction, structural condition improvements, prioritization of sanitary sewer assets, and regulatory compliance.

Titles from this speaker

Description: Modeling Rain-Derived Inflow and Infiltration (RDII) Sources in the Absence of...

Modeling Rain-Derived Inflow and Infiltration (RDII) Sources in the Absence of Condition Assessment Information

Abstract

Typically, inflow and infiltration (I/I) sources are identified during condition assessments; however, knowing where to begin with your assessment efforts can be difficult to determine. Flow monitoring can prioritize flow meter basins for further study, but this approach presents a host of challenges with well over 1,000 flow meter basins. With an impending consent decree, the City of Houston needed an out-of-the-box solution to assessing their 1,500 flow meter basins. So the City and RJN set out to tackle the challenge of modeling I/I to create a prioritized assessment program, affectionally called the 'I/I Cafeteria Plan.' The City wanted a way to prioritize meter basins and estimate quantities of I/I while idenfitying potential I/I sources-manholes, gravity mains, service lines, etc. This tool would consider the unique challenges for a flat coastal city with no zoning regulations and would ultimately enable the City to efficiently and cost-effectively implement I/I reduction solutions. A phased approach was identified as the most pragmatic course of action, and four phases were established; Phases I and II created the framework of the model, Phase III calibrated the model, Phase IV will implement modeling automation solutions. Ideally, during the first two phases, characteristics such as age, material, size, elevation, grade, soil type, groundwater level, surface cover, and drainage area would be used to complete an evaluation. Unfortunately, the City's GIS lacked systemwide data for several of these characteristics, so it was decided that the model would be established with the following criteria:
- age, size, and material would be used for gravity mains;
- parcels would be used for service lines;
- and age alone would be used for manholes.
RJN's prior work throughout the City's sewer system provided a large dataset to fill gaps and establish the model framework through a desktop study.
The results of Phases I and II included the development of recommendations and their associated costs. This combination of characteristics divided the City of Houston's gravity mains into 120 different classifications. Estimated I/I rates per foot were developed for gravity mains based on actual observations from the City's and RJN's data sets. Available data for service lines was minimal, so it was decided to use parcel data to represent connection points to gravity mains. Equations were developed to estimate the number of defective parcels per study area and the number of defects found on defective parcels. An average I/I per defect was then applied to each defect in the area to determine the total estimated I/I coming from service lines. The City conducted a prior ponding analysis which provided the model with the ability to calculate inflow from pickholes for a manhole when the cover type was known. For manholes, breakpoints for age were established based on changes in City design practices, such as the transition from vented to concealed manhole covers. The size and quantity of pickholes per cover could then be determined using standard City construction details.
Phase III condition assessments filled in the data gaps identified during the initial phases. Data collected during this phase was used to calibrate the model. Phase IV is slated to begin in 2021 and will encompass the development of a customized software application to automate much of the model run while integrating into other City programs to share data and continue to refine the estimates the model generates.

Inflow and infiltration (I/I) sources are identified during condition assessments; however, knowing where to begin assessment efforts can be difficult to determine. Flow monitoring can prioritize flow meter basins, but this approach presents challenges when working with well over 1,000-meter basins. Houston needed an out-of-the-box solution to assessing their 1,500-meter basins. So, the City and RJN set out to tackle the challenge of modeling I/I to create a prioritized assessment program.

SpeakerNickel, Tristan

Presentation time

15:35:00

15:50:00

Session time

15:30:00

17:00:00

TopicIntermediate Level, Collection Systems

Author(s)

Nickel, Tristan

Author(s)Tristan Nickel1; Jack Canfield2

Author affiliation(s)RJN Group, Dallas, TX1; Houston Public Works, Houston, TX2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158696

Volume / Issue

Content sourceWEFTEC

Word count15

Unifying Strategies for Wastewater System Revitalization: Lessons from the City of Copperas Cove

Abstract

Driven by a commitment to reinvest in its wastewater system and spurred by a surge in development, the City of Copperas Cove embarked on the formulation of a tangible Capital Improvement Plan (CIP). The primary objective was not merely to assess the system based on its condition or capacity individually but to amalgamate these perspectives into a comprehensive CIP. The initiative aimed to develop a project that would scrutinize both the present and future capacity of Copperas Cove's wastewater collection system, concurrently establishing a framework for a condition assessment program. This undertaking involved the installation of 16 flow meters across the collection system, GPS data collection for 75 manholes, and the inspection of approximately 15% of the system, encompassing manhole inspections, smoke testing, and CCTV inspections. The installation of flow meters occurred from September 22nd to December 1st, 2022, during which various rain events were documented to calibrate the hydraulic model. A comprehensive hydraulic model was crafted to assess the capacity requirements of the sewer collection systems. Calibration of the model utilized flow monitoring data from all 16 meters under both dry and wet weather conditions. InfoWorks ICM, employing Wallingford's fixed runoff methodology and the groundwater infiltration model (GIM), was used to calibrate the model's hydrology. This dual-method approach enabled simulation of the City's rapid inflow responses and the slower infiltration of groundwater into the sewer collection system. The calibrated model facilitated a detailed analysis of the system's performance, addressing concerns related to small- and large-diameter pipes, lift stations, and forcemains upstream of future development areas. The Inflow and Infiltration (I/I) analysis from the flow monitoring efforts revealed that quick response inflow posed more significant challenges to the City than infiltration responses. Approximately half of the City experienced excessive inflow, with a quarter nearing the threshold of 10,000 gpd/1,000 lf of inflow. While this typically calls for prioritizing a condition assessment I/I removal program, the City's intention to create prompt action construction packages that factored in capacity needs led to discussions about capacity restrictions when determining condition assessment locations. Crucially, the analysis highlighted that areas where the City faced capacity issues were not necessarily the same areas with the most I/I. This prompted a decision-making process on whether to target I/I location and removal or identify condition issues in areas requiring capacity improvements. The timing of capacity improvement needs was also a factor in determining locations for condition assessment, prioritizing areas with existing capacity concerns related to the current level of service/development. This strategic approach allows for a systematic, comprehensive effort across the City. As part of the project, the City initiated a planned condition assessment program, involving manhole inspections, smoke testing, and CCTV inspections of targeted wastewater gravity mains. The evaluated assets were assessed for structural integrity and sources of inflow/infiltration. The program was designed to identify both public sector and private sector sources during field investigations. While public sector sources will be integrated into the CIP, the City plans to address private sector sources primarily based on the results obtained from smoke testing. While the City remains focused on CIP projects to alleviate capacity constraints for future development, it also intends to address larger inflow areas as funding becomes available, recognizing the impact on overall wastewater treatment capacity.

Our paper explores the integration of hydraulic modeling and condition assessment to create comprehensive Capital Improvement Plans (CIPs).

SpeakerNickel, Tristan

Presentation time

09:30:00

09:45:00

Session time

08:30:00

10:00:00

SessionPlanning Techniques to Support I/I Mitigation, Master Plans and Design

Session number302

Session locationRoom 356

TopicAsset Management, Collection Systems, CSO & SSO Planning and Mitigation, Intermediate Level