Bluffs

013 bluffs east end 01

Bluffs like this on along Birding Island ringed the entire lower Payette Valley and became its outline. Around the west side of Fruitland, the bluffs along the Snake, are called the “Palisades.”

Just down this dirt road (unblocked back then) was Charlie Johnson’s farm/ranch, stretching from above the Bluffs clear to the river.  This stream is a very placid branch of the river that NP folks, including my family, thought was the perfect place to picnic and swim.  Charlie’s cows kept the trees and brush down and the closely cropped grass was very like a public park and picnic ground. My family and dozens of others would picnic and swim here through the 30s and 40s.

We would climb the sand sliding down the Bluffs.  Often in those slides we would find chunks of black obsidian 6-10″ big.  These were rounded showing that they had been carried and cobbled by river water from some distant place before the Bluffs were formed.

This river branch was the old main river channel until diverted in teens.  The constant flow of sand from the bluffs meant that the stream was very silty, with the middle being only inches deep–a perfect place for families with very small children to swim.  The stream ends at a diversion dam funneling the water into the Payette Canal.

Back at the end of the last ice age 10-11,000 yrs ago, glacial deposits left the entire area between the large mountains a large, jumbled plain of almost pure sand — just rolling hills, such as you see now up the Willow Creeks, and just south of New Plymouth.  Also deposited onto this jumbled plain were vast quantities of wind blown sand and “tuffa” (volcanic dust) from Oregon.  The farther west one goes in Payette and Treasure Valleys, the higher the percentage of wind blown sand versus glacial sand.  The western wall of Treasure valley is almost entirely wind blown sand.

Also contributing to all the sandy hills was the Great Lake Bonneville flood hat broke through at Red Rock Canyon, Idaho and emptied catastrophically into the Snake filling it brim to brim, and forever changing the character of its banks.  It brought huge deposits of alluvium from Utah. In Hells Canyon, about 50 miles downriver, one can still see the terraces high up on the hills left by this enormous flood.

Then the Snake River cut through that sand establishing the present Treasure Valley.  Simultaneously the Payette also cut down thru all this sand from Emmett to the confluence.

Unlike the Snake’s flood plain, the Payette’s headwaters had no intervening valleys to dump its accumulated alluvium.  So into this large cut it dumped all the alluvium from its entire watershed.  This created a “bench” or secondary flood plain that created, what I call the Plymouth Bench and the “peninsula,” the raised portion upon which sit Fruitland out just past Gay Way Corner overlooking the Payette’s last bridge in Payette Valley, and melding in southward into the same original sandy hills.

Thus the Gay Way corner area is really on a bluff/peninsula, or bench, sort of thrusting into Treasure Valley.  Thus was created the perfect place for fruit.  Being above the present rivers’ floodplains meant that it was also above the coldest air.  Being on a 100% alluvial bench meant deep soil, better than any other competitive sites in the area.

After dumping all its alluvium, filling its valley, the Payette again cut down thru that alluvium creating its current or lowest flood plain.  This lowest flood plain extends from Emmett to the confluence — and a large area of sloughs (7 mile slough) that continued, at one time all the way to Weiser on the east side of the Snake.

This lowest flood plain is characterized, not by alluvium, but by mostly cobbles and thin soil.  Subsequent floods have deposited some new  alluvium on the south side of this lowest flood plain just west of Emmett, and continuing to Hamilton Corners — this is farmable cobbled flood plain, but just doesn’t have deep soil, because it is a thin layer on top of the cobbles underlying it.  The present river in this area is a braided stream meandering across its present flood plain willy-nilly changing its course.

Before the dam was built, each spring ice melt meant ice dams along this section, each diverting the river to a new course, again and again.  The last such spring thaw and ice jams was winter of 1948 which saw the river freeze over below the dam, and subsequent ice dams form.  These “took out” the new bridge on Hwy 52 to the east end of Birding Island, And the Falk bridge.

In the early 1900s the river ran right next to the bluffs, but a serious ice jam changed its course to the present–the last of probably innumerable times in the past.  Blocking the Payette with multiple dams put an end to the willy-nilly back and forth braided stream of past millenia.

Looking from Ontario at the east bank of Snake, it looked exactly like this above photo.  Until just recently.  This bluff is now occupied by the bedroom community of Fruitland.  As farming and housing occupy more and more of the bluff areas surrounding the Payette valley, these bluffs erode very quickly, and grow lots of vegetation changing their original appearance and disappearing the “bluff” or palisade look.  Farming and building also tend to smooth out and blend in the lip.  Look at the bluff now inside Payette city’s eastern boundary — except for a rise in elevation, the bluff has disappeared.

This eastern bluff is interrupted at the “point” of the peninsula by the Payette Valley, but continues after the Payette Valley, past Payette, and on to the next river cut, the Weiser (Cove area).

Up the Payette, this same bluff (on both sides of the river) continues to above Emmett to the narrows where more recent lava flows interrupt the river, and where the dam was sited.  Black volcanic rock gave the canyon and dam its name.

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