The vast watershed of the Missouri River extends from the Continental Divide of Montana, Wyoming and Colorado to the mid Mississippi Valley; like a giant funnel, it narrows from west to east and is restricted to the State of Missouri on the final leg of its journey. On my frequent travels between our homes in Columbia and Littleton, I cross a large segment of this watershed; indeed, on my route across the Great Plains of North America, almost every stream, creek, culvert or rivulet that I encounter is flowing toward the Missouri River. An exception occurs in eastern Colorado where, for about 10 miles on either side of Limon, I-70 dips into the watershed of the Arkansas; east of Limon, the highway descends from the High Plains escarpment while, north of town, it climbs back to the Missouri watershed at the crest of the Palmer Divide.
While the Upper Mississippi Valley has endured heavy rains and flooding over the past few weeks, the Missouri watershed seems to have recovered from a wet June and is back on its seasonal course. On my trip to Colorado, yesterday, I found that the Missouri River floodplain, just west of Columbia, is no longer in flood stage and that large flocks of great egrets have gathered to hunt in the remaining pools. Farther west, the Flint Hills of eastern Kansas, emerald green in June, have faded to a drier, olive tone. The corn stalks of Missouri and eastern Kansas are beginning to wither while the irrigated fields of the High Plains retain their deep green color, in sharp contrast to the browning grass that lines the highway; scraggly clumps of prairie sunflower also adorn the High Plains in August, hardy cousins of the cultivated sunflowers that now produce brilliant carpets of gold.
The seasonal pools and farm ponds of the Great Plains are beginning to contract in the summer heat, offering mudflats and moist grasslands for shorebirds that now stream south to their winter beaches. Flocks of Swainson's hawks, preparing for their upcoming journey to Argentina, soar above the drying landscape and, in eastern Colorado, pronghorn, gathering ahead of the autumn snows, share the yellowing grasslands with herds of cattle. In the higher, western reaches of the Missouri, winter is never far away.
