Consideration and Approval of Mitigation Assistance Agreement:  between the City of Flagstaff and Arizona Department of Emergency Management and Military Affairs for Raingauge Network Expansion.

The proposed Agreement will help the City continue to expand its Flood ALERT precipitation and stream gauge system.  This system is integral for natural disaster alerting and rapid response for Arizona communities. The City installed three ALERT gauges in 2004 and have slowly expanded the system to include nine rain and stream ALERT gauges. Flagstaff has critical data gaps in the network due to the extremely local nature of the monsoon storms in the Arizona high country. 

Water Services will match 25% of the grant, in the order of $27,574. This amount has been budgeted in this fiscal year 2019-2020 for expanding the rain gauge network. This grant will leverage our existing plans to expand the gauge network.  There is $40,000 in the FY2019-2020 budget in account number 206-08-331-1250-0-4461.  The remaining budget appropriation will come from 206-08-375-3454-0-4433.

The grant will accelerate, and enhance, the ability of Water Services - Stormwater to provide early warnings for floods, measure climate change, and model City infrastructure for flood conveyance.

The flood ALERT network (also called the raingauge network) works towards the Council Goals of "Transportation and Other Public Infrastructure", "Climate Change", "Environmental and Natural Resources", and "Community Outreach".

We have no knowledge of previous Council involvement/consent on the City's flood ALERT gauge system.

This grant will accelerate an already developed plan within Water Services - Stormwater Section to gauge every FEMA stream course in the City limits. There are no other viable options or alternatives.

The Flood ALERT precipitation and stream gauge system is integral for natural disaster alerting and rapid response for Arizona communities. The City of Flagstaff installed three ALERT gauges in 2004 and have slowly expanded the system to include nine rain and stream ALERT gauges. Flagstaff still has critical data gaps in the network due to the extremely local nature of the monsoon storms in the Arizona high country. For example,  in the summer of 2018, there was a single-day monsoon storm event; it was recorded as a 5-year event at some gauges, a 50-year event at one gauge, a greater than a 100-year event at some County gauges, and estimated to be a 500-year event in one Flagstaff neighborhood that is ungauged. Localized flooding was severe in some areas while there was nothing to note just a couple of miles away. The extremely local storm patterns require the City to expand our ALERT network to better allow for early warning for residents and emergency services and to provide critical historical data for budgeting, designing and implementing appropriate stormwater conveyances.

The City is currently designing the complex Rio de Flag drainage system, in conjunction with the Army Corps of Engineers. This project is estimated to cost nearly $100 million dollars to alleviate flooding in downtown Flagstaff. The tributaries, and associated catch basins, are not included in this project. This upgraded flood ALERT system will help the City determine which catch basins will need to be up-sized to connect to the new Rio de Flag stormwater system. Long term trends in rainfall-runoff, flooding intensity, and precipitation patterns can be useful not only for Flagstaff but for similar high elevation communities in Arizona and western New Mexico. A fully developed ALERT system, therefore, would provide many benefits to the City of Flagstaff and for the region.

This grant will help fully implement an internal plan in the Stormwater Section to gauge every FEMA stream course in the City. Once this grant is fulfilled the City will have a comprehensive rain and stream gauge system that will benefit the community, planners, and flood designers.

The community will receive a more comprehensive flood alert system and also more appropriate future designs for storm water conveyance and flood proofing.