It's been almost two years since a storm generated a massive wall of floodwater that rushed into Madison Valley and drowned resident Kate Fleming in her basement. And although the wheels of city planning turn slowly, Seattle Public Utilities is getting closer to solving part of the problem by expanding the existing detention pond at 30th & E. John.
They're holding a public meeting tonight to review the 30% complete designs for that location.
Right now the block is just a sloped hole in the ground with grass and a couple of benches. And while the intent of the project is to expand the size to accommodate more water, they're also intending to spruce it up to make it more of a neighborhood amenity.

Existing Madison Valley Flood Control Pond
One big change in the new plans is to add many more trees all around the property:

They're also regrading the depression into a series of terraces that would make the space more walkable, with several new pathways, bridges, and a dry creek bed at the bottom:


Construction could begin by late next summer.
A following phase will connect this project to a big new overflow drainage pipe that will empty onto an area near the baseball fields in the Arboretum, on the north side of Madison.
Another one of big issues effecting the whole valley has been clogged storm drains and blocked up drain pipes. Part of the cause of the flash flood that led to Kate Flemming drowning was lots of storm drains up-hill from the valley being blocked with leaves. So, this is one thing we individuals can keep an eye out for, and prevent / fix ourselves in many cases.
I don't know much about it, but SPU now has an "Adopt a Drain" campaign that might be helpful:
http://tinyurl.com/35porl
With the larger drain blockage issue, we've seen SPU trucks out regularly over the past months running cameras down the drains to check for blockage, and flushing the drains out with water (they fill at our nearby fire hydrant).
And, if I understand correctly, the big new overflow drainage pipe project will provide a way to get an even larger volume of water out of the upper valley (e.g., off Madison) before it runs down the hills and gets down to the bottom.