BRASSONBRASS: i'm not pretending to be an expert on this, but i can give you a little info that might be useful.
alkali lake: i have never fished it, but my understanding is that it is a rather shallow lake, which would mean it would ice up early on. a couple of weeks ago it had ice around the edges near lenore; i haven't driven by it for 10 days or so. frankly, i'd not try for walleye there. bass and perch, perhaps. while there is an unimproved place you could probably launch a trailered boat (ice permitting), a cartopper might be more appropriate.
billy clapp: billy is part of the columbia basin irrigation project, and as such is subject to water level fluctuations throughout the year. i'll attempt to attach a photo of the launch area taken about 10 days ago: the lake level now is WAY below the end of the launch ramp, and the mud below the ramp makes cartopper launching the only alternative, as long as you don't mind dragging a skiff through the mud. billy clapp is at it's "high water" level from roughly late march (when irrigation water begins to flow into it) to october (when the irrigation season shuts down). but beware: on warm summer weekends the water skiers and jet skiers will make fishing after maybe 10 am a lot less desirable. last summer i caught a keeper walleye in billy, while trolling at 60 feet for trout (surface water temp was 70 degrees or more then). water that flows into billy comes out of banks lake, so presumably fish that are present in banks would also be in billy.
so where do you fish for walleye in the winter/spring? again, not pretending to be an expert, i'd head for potholes reservoir. while the water level is "down" there, too, it is accessible from the southerly launch ramps. roughly, potholes is at it's lowest level around november first, and at it's highest level around memorial day. but it is a deep reservoir, and big. perhaps the folks at mardonresort.com can give you advise.
banks lake has a great walleye reputation, but for some unknown reason 2003 has just not been a hot year there. i caught one keeper there this year.
no doubt other folks have other ideas on where to head for winter/spring walleye. email me at johnrobyn98851@yahoo.com if 'ya want to discuss this further.
