Defensible & Repeatable Capital Planning at North Charleston Sewer District

The Background

North Charleston Sewer District (NCSD) services wastewater for approximately 33,000 customers, making up a population of just over 115,000 people. The service area is approximately 60 square miles in three different counties and includes six municipalities.

In terms of assets, NCSD manages approximately 480 miles of a gravity collection system, 35 miles of force mains, 11 miles of identified lateral connections. In total, the linear asset network is between 520-530 miles. The piping infrastructure ranges from 4 – 78 inches in diameter, with the largest pipelines near the 32 MGD wastewater treatment plant (WWTP). The WWTP has 60 pump stations, and the gravity collection system includes just under 11,000 manholes.

From mapping to advanced analysis and work order planning

NCSD standardized to a GIS database as its “data of record” in 2001. With a mature GIS, NCSD has a majority of its infrastructure with asset descriptive information readily at hand.

In addition to its GIS database, NCSD also utilizes GraniteNet software to collect CCTV inspection data and Lucity as the District’s computerized maintenance management software (CMMS) to coordinate and track work orders and scheduled projects.

NCSD needed a software to help bring these different data sources together to make more informed capital improvement project (CIP) planning decisions. NCSD chose Innovyze’s InfoAsset Planner for this purpose. InfoAsset Planner has allowed NCSD to organize asset data across multiple tools and communicate CIP decisions in much more transparent and defensible ways. With InfoAsset Planner, $1.2 million in CIP projects has been determined, communicated, and approved with no questions asked.

The Challenge: Determining what assets to service, and when

The ultimate problem was addressing aging infrastructure. For NCSD, the average age of their underground pipe network is ~41 years. Some portions of the NCSD underground network date back to the 1600s. Many parts of NCSD’s system now age between 1930s and 1950s while others age from the 1980s.

NCSD wanted to make sure that it was efficiently and effectively going to be able to schedule the inspection of these assets - and the review process of those inspection records - to budget and plan for ongoing capital improvement programs.

The Solution: Risk-based and prioritized asset planning

NCSD onboarded Innovyze’s asset repair and capital project prioritization software to help address the R&R of an aging wastewater transmission and collection system. With the use of inspection records (both internal and external), as well as data from the recommended capital planning efforts, NCSD could begin to substantiate the work that needed to be done to the specific assets – so that the R&R budget could be justified, as well as defended to - and by - the overseeing Commission.

Developing a prioritization framework

NCSD catalogs condition assessments from the CCTV data and creates risk scores for assets and provides recommendations for R&R. This framework prioritizes the riskiest assets so that intermediate inspections can be scheduled to understand impacts on deteriorating assets. Unweighted factors – such as work order history, proximity to critical facilities, and pipe material/size - are analyzed to produce a 5x5 Bi-Directional Risk Matrix. This information is then used to visualize the length of pipe and percent of total length at each stage of criticality.

This allows NCSD to maintain a realistic multi-year capital plan.

The Result: Confidently prescribing the right renewal actions at the right time, and the right cost

A rehabilitation plan generated by InfoAsset Planner is funneled into and processed through NCSD’s Rehabilitation of Lines Program and Capital Budget so that proper funds are allocated accordingly each year by asset.

This program is completed for all pipelines, manholes, and laterals. The asset repair and capital project prioritization software allows NCSD to use a methodology that is configured on the NASSCO systems and the NASSCO 6.0 codes coming from the CCTV inspections.

Consistently, NCSD can confidently rely on the cost table generated by InfoAsset Planner. In one case, the forecasted budget was within 3% of the capital funding actually needed to complete a round of R&R projects.

In conclusion, NCSD is in great standing with the state and federal environmental governing bodies, in part due to the sound stewardship of the District’s assets as led by its Capital Projects Division staff. This philosophy of high-performance, founded on sound asset management concepts, has driven the culture at NCSD. They are empowered to be focused on managing their wastewater transmission and collection system with the utmost fiscal, environmental, and community-focused responsibility in mind.

Click here to see an example of NCSD's work with this interactive Esri Story Map.

Utilities of Any Size can Prioritize Capital Planning