Silver Bow Kiwanis

Silver Bow Kiwanis Kiwanis Club Meeting, Aug 30, '11

12:00-1:00 Tuesday, August 30, 2011

Larger map and driving directions

Butte Perkins
2900 Harrison Ave.
Butte, MT 59701

Dave reminded everyone of the Tech football game this coming weekend. It's an evening game, so we need to have people there at 4 when the gates open. Kickoff is at 6. And remember, there are three entry points, so we really need at least 5, but preferably 6 or more people.
Jack reminded us of the cleanup on September 10 at 10. We're meeting at Clark Park.
We now have some fliers to hand out, so if you want to invite somebody to a meeting or to join, or if you want to remind someone of something we're doing, you can give them a flier as a reminder. Keep track of who you're giving them to, as there may be an incentive...

Tim introduced our own Steve Hess to talk about new floodplain mapping. The "current" maps are from 1979 surveys and were either adopted in 1979 or 1982, and in some cases these maps were inaccurate or are now outdated, and in almost all cases, the scale of the maps made it very difficult to determine whether a property - or more importantly a structure was in the 100 year floodplain.

FEMA has mandated that all floodplain maps have to be updated, but this process takes time. Just for Silver Bow County, it has taken 3 years, and most of the maps have not been re-surveyed since only some areas needed to be updated.

The biggest improvement is that the maps are all being digitized, so there are now maps that have an overlay of an aerial image so that properties and structures can be more accurately placed in relation to the 100 year floodplain.

These maps are either detail surveys or undertimined floodplain maps. Detailed surveys will include the floodway (where most of the flood water goes in a normal year) and the 100 year floodplain (which is where additional water goes when the floodway capacity is exceeded. The delimiter of the 100 year floodplain is the point to which water will only have a 1% chance of reaching in a year (just because the water reaches the 100 year mark one year doesn't change the 1% chance that it could reach the 100 year mark the following year). Undetermined floodplain maps will show an estimate of the 100 year floodplain based on a less detailed examination of the ground contour, and are usually used in more rural areas. If your property is on an undetermined floodplain map, then you may want to pay for the surveys to get the floodplain properly mapped and filed so that you can build in an area that is less likely to experience flood damage.

The largest problem area in Butte is along Blacktail Creek, where many homes, many with basements, were built in the 100 year floodplain before the floodplain was mapped in 1979.

The two areas in Silver Bow County with the most significant changes in the mapping are Sand Creek along Harrison Avenue, where a diversion was put in place to shift floodwater across the airport property and away from homes and businesses, and near Melrose and Divide where the land was re-surveyed in the late 1980s, but those surveys were not adopted by FEMA until now.

The new maps have to go through review and public comment, which should be happening in September, or maybe early October, and then need to be officially adopted by January 15, 2012.

Presentation
Steve Hess, Digitized Floodplain Maps
Menu
Chicken Strips and Fries
Attendees
19
Event Updated
5:05 Tuesday, August 30, 2011