"Fish gotta swim," goes the Showboat song. Fish also have to breathe, and both functions come easiest when there's water around.

Every drop helps in a river like the lower Arkansas, where dam releases swing seasonally from raging on behalf of irrigators to flat-out stagnant.

Now, a few extra drops have been freed to freshen the river during those thirsty times below Pueblo Dam.

Thanks to some creative water finagling by the Colorado Division of Wildlife and State Parks, trout pampered by $7.5 million in recent stream improvements through the City of Pueblo will have minimum flows for swimming and breathing.

The parks and wildlife agencies last week agreed to split the cost of leasing 3,082 acre-feet of water from the Pueblo Board of Water Works. The water will be doled out through Pueblo Dam when needed as 50 cubic-feet- per-second minimum flows.

More than 100 miles downstream, the same water will boost John Martin Reservoir's permanent pool and keep fish alive there when water is almost exhausted, as it was late last summer.

Grady McNeill, water-rights specialist for the wildlife division, said it's not a lot of water, "But it is if you look at what could happen."

What happened in 2005 was that late summer flows out of Pueblo Dam fell to 5 cfs, roughly nothing. Trout in Pueblo's proud, new 9-mile fishing and kayaking park nearly went belly up. John Martin transformed last year into a mud flat with shallow pools.

"When we'll see the benefit from the release is in August through September," McNeill said.

Wednesday, the designer trout stream below Pueblo Dam flowed at 24 cfs - not great for fishing but enough to keep trout wintering safely.

"The water is low and cold, and the fish are spooky and holding in the deep pools," said David Ritchie, manager of ArkAnglers fly shop in Pueblo.

Ritchie said the stretch, which the U.S. Corps of Engineers and other agencies revamped with wing dams, pools and reinforced banks, fishes best from the dam to 6 1/2 miles downstream.

Besides 10- to 14-inch stocker rainbows, which are "hauled out of there pretty quick," he said wild brown trout up to 22 inches swim in the stretch.

Downstream near Kansas, the newly acquired water will keep a minimum pool in John Martin sufficient to prevent a total wipeout of fish after irrigators take their lion's share of water.

Last summer, the big reservoir shriveled to fewer than 800 surface acres. (In a good water year, John Martin will spread over 15,000 surface acres.)

Many fish shot through the dam and met their demise in Kansas corn and wheat fields. The few saugeyes, crappie, bass and wipers that remained were steeped in small, sun-heated pools near the dam but avoided dying off.

If irrigators had called for more water, John Martin could have shrunk to a volume of 500 acre-feet, (about 300 surface acres), which was all the water the wildlife division owned for fish.

A total fish kill likely would have ensued.

The new water will build John Martin's minimum pool for fish up to about 3,000 acre-feet (800 surface acres), not great, but helpful.

Now in the winter storage season, the reservoir has swollen to a plump 14,000 surface acres. It will rise more when mountain runoff begins, but it is sure to fall again later in summer.

The newfound water literally could give two major fisheries new leases on life.

dentrye@RockyMountainNews.com