The Importance of SUE - Part V

Water is one of the most important substances on earth. Yet, many of us take for granted how the water we drink and use daily actually reaches us. While water and wastewater projects are typically performed within roadways full of crossing utilities, the design of potentially new water pipelines may involve rural locations with many property owners and right of way impacts, all of which pose potential challenges during design and construction. Wastewater systems designed for gravity flow rely heavily on a continuous, downward sloped pipe to maintain flow. Existing utilities will play a major role in the design of gravity flow systems, especially if the design is through a heavily congested area. Are you factoring in the potential impact of the existing utilities into your design or project?

The Problem

How do you properly design a gravity flow system to weave through a maze of crossing and parallel underground utilities, all at different elevations? What if you are 95% complete with construction and encounter a 48” Reinforced Concrete Cylinder Pipe waterline that, according to records, was “supposed” to be at a different elevation? Or more likely, what if you encounter a massive fiber duct during construction of a waterline that you had no records on at all?

Existing utilities are often an afterthought, and the responsibility is often dumped on the contractor to “deal” with them during construction, which will undoubtedly lead to change orders and construction delays. Not fully accounting for existing utilities during design is both inefficient and highly expensive, so utilities often cost more by not performing SUE during the design phase.

The Solution

Luckily, there is a proven solution to help mitigate these unforeseen conflicts with utilities. Having knowledge of the existing utilities, both horizontally and vertically, during the design phase of waterlines and especially gravity flow wastewater systems can help eliminate conflicts and reduce change orders during construction due to utility conflicts. TRG recently provided SUE services on the Beck Branch Wastewater Interceptor Improvements project for the North Texas Municipal Water District. After QL “B” SUE field work was completed, and a conflict analysis was performed, TRG excavated over 30 test holes. This work confirmed that there were several major storm lines in direct conflict with the proposed interceptor. Based on TRG’s findings, the entire alignment of the interceptor was adjusted to avoid those conflicts. Our SUE services were used by the City of Austin to help choose an alignment of a proposed 24 inch Onion Creek Reclaimed Water Line. The proposed alignment traversed the Roy Kizer Golf Course, the Onion Creek Soccer Complex and several adjacent residential subdivisions. TRG provided QL “B” services within 25 feet on each side of the project.

Applying SUE

TRG recommends that the proper steps are taken, according to ASCE publication CI/ASCE 38-02 Standards, to ensure that both Quality Level “B” and Quality Level “A” SUE are completed during the design phase and incorporated into the design decisions. Once QL “B” SUE (the horizontal designating of utilities) has been completed in the field, a full conflict analysis will be conducted and potential conflicts will be identified. QL “A” SUE test holes (the uncovering of utilities that provides precise vertical and horizontal data) will confirm the utility elevations of the potential conflicts so the existing utilities can be factored into the design.

Let The Rios Group provide responsive, reliable, results on your next project before it is too late. We are happy to host a Lunch and Learn on SUE and Utility Coordination for you and your team. Feel free to contact us in North Texas at 817.345.7500 or in Central Texas at 512.580.5440.