Hard times sometimes call for hard choices. And in today’s economic climate, those choices often must extend to every aspect of infrastructure maintenance and operation. For example, for stormwater system asset management using GIS, which stormwater features should you collect to provide sufficient information without wasting resources?
Jackson: I really hate to start by saying, “Well… it depends,” but, in fact, it does. Stormwater system asset inventory collection priority depends on what you are trying to accomplish. We have a saying in GIS: “Always start with the end in mind.” This is one of those starts.
Data collection also depends on the size of the budget, and these days, when you don’t have much money and you need it to go as far as possible, my recommendation is to start with a well-developed work plan that supports a clear and simple focus on the project outcome.
If the project’s supporters (champion and budget) are from the engineering department, then the project focus might be modeling, and your priority would be to collect and check thoroughly the elevations and inverts — all at survey quality. However, if your town manager or public works director has been alerted by citizens of stormwater debris overflows, then maintenance crews don’t need rim elevations or inverts to do their jobs efficiently. For them, a basic mapping-grade point that shows the location and photo of the curb inlet with related maintenance history would be a great start.
The next steps in any project are determined by scope, schedule, and, of course, fee. A stormwater asset inventory project is no different. To end up with a usable product, you must start with clearly defined goals and objectives, and a good dose of budget reality. Hard times call for hard choices, and it’s your choice to make the best decision possible.
Civil engineer’s perspective
Rose: I certainly agree that “it depends” on what you are going to use the information for. And you are absolutely right to use Stephen Covey’s phrase, “Begin with the end in mind.”
My concern is that the “end” must not be too shortsighted. One department may be interested only with the location of inlets and manholes… today. But once that department gets that information, someone is going to ask how all those inlets are connected. That means another trip to the field to verify connectivity. And the next question will be, “What size pipe is connecting those two inlets?” which could mean another trip to the field. And then someone is going to ask “How deep are those inlets?” and the crew will have to go back out again to get the invert data.
This is all to emphasize the point, “Begin with the end in mind.” Today, all you may need is locations of inlets, but what will you need tomorrow?
On a recent project, a municipality had located the inlets; verified the connectivity, material, and pipe sizes; and even obtained rim elevations. But there were no depths or inverts. A new development is now connecting to the upper end of the stormwater system. Does the downstream system have sufficient capacity? We don’t know because we don’t have the data to model the system. The only way to get the data now is to send the survey crew out again. And that costs more money.
Instead of limiting the data obtained, maybe limit the geographical area. Do what you can with this year’s budget and add to it next year. You’ll reach the “end” much faster… and cheaper.
|Gordon Rose, P.E., senior project manager at McKim & Creed, has 30 years’ experience in water distribution, wastewater collection and treatment, stormwater management, and planning.
Janet Jackson, GISP, heads McKim & Creed’s GIS activities company-wide. McKim & Creed is an engineering, surveying, and planning firm.
Contact Rose and Jackson at firstname.lastname@example.org.