From Traffic to Tangerine

Yesterday was my day with the Engineering Department. This is a division of Development Services and is supervised by the Town Engineer, Keith Brann.

I started out the morning with Keith discussing the flood plain map, which will go into effect on Thursday June 16! Citizens have been informed that their land might be in the new flood plain, but the changes only affected 3 square miles. This came out of a vigorous debate with FEMA in order to determine an adequate and fair flood plain distinction. FEMA wanted to just assign a broad swath of land without the specific distinctions and the Town was able to fight to get the best representation of what the water might actually do. It seems like that action set a precedent for other jurisdictions to be able to negotiate their flood plain assignments with their own survey and study data. There is a lot of water issues that the Town has to worry about and the flood plains and watersheds are very important. These can impact the homeowner’s insurance and FEMA collects new flood insurance premiums. There are some thing the Town is working on to get some areas of out the flood plain, like the wall around San Lucas. 

I went with Keith to the Development Engineering Staff meeting early in the morning. In that meeting I felt that I got a good overview of what responsibilities the department has. They focus on drainage, the Tangerine expansion, private construction, grading, environmental issues, traffic issues and plans review. The development engineers work with a project from the beginning, remember those development coordinators and pre-application meetings, these engineers are involved in those as well. They provide their best engineering judgement when it comes to plan reviews and new development. These guys are involved in any type of building from residential to commercial. The environmental engineers make sure that development is compliant with any federal regulations. Things like USDA, Army Corps of Engineers, and Endangered Species lists. These engineers look more at the big picture rather than at an individual residence. They also work as the liaison for CIP and the Federal government.

The final area is Traffic Engineering, and I spent some time with Fernando Prol, the division manager. He gave me a great overview of what his division does and how it fits in with the rest of the organization. He and his team put together studies of traffic trips and the impact that those travelers have on the roads. They make recommendations for new infrastructure for private developments and subdivisions. The traffic engineering does this same process for capital improvement/public projects. They also respond the citizen reports and conduct studies on speed zones, traffic circles, school zones, and multi-way stops. There are so many variables and different ways that these reports can be interpreted, so usually the engineer sticks to what was originally agreed upon in the plans review. Fernando gave me a map of how the traffic was re-routed after the Twin Peaks Interchange was completed. Traffic was reduced on Cortaro by almost 10,000 trips!

The second half of the afternoon I spent in a design meeting for the Tangerine Corridor that mainly dealt with drainage and the movement of the road, once the project gets initiated. This meeting has representatives from Oro Valley, RTA/PAG, the Pima County Flood District, and the consultant hired to conduct the engineering study. This was very technical and some of it went over my head, but they are worried about the huge watersheds that will run right over the road. There is concern about what to do when these have a 100 year flood. There was discussion about the size and materials needed for the culverts and how to best get animals across the road. 

These were some of the most impressive people I have met (everyone here is crazy smart). Determining flood plain and culvert dimensions for all different scenarios was extremely detailed and the ladies and gentlemen in the engineering department know it all. What I gained from this is that reinforced concrete (steel encased in concrete) is the best material to use, and a 100 year flood is a probability of rainfall during the current year, not that a flood like that will happen every 100 years. Lesson learned.