Friday, December 7, 2007

Big Arizona Rivers

When I was (forced) transferred to the Phoenix, Arizona - which is another story - I drove the less travelled highways from Eugene to Phoenix to get a sense of the country, the eastern side of the Sierra mountains, Nevada's basin and range mountains, and northwest Arizona. In Arizona drove from Kingman through Wikieup to Wickenburg into Phoenix. It's a 3 hour drive through the open desert. I didn't realize two years later I would be driving this highway once a month as part of a field trip.

While I was driving I kept an eye out for "rivers" or what I thought rivers would look like. I had never been in Arizona so I had no idea about desert rivers let alone big desert rivers. The first of these was the Big Sandy River. I approached a long bridge where the sign of the river was noted. I crossed what seemed to be just more desert except it was a few feet lower than the surrounding desert.

Near the middle there was this small, 10 foot wide, stream flowing, more wandering within a 300-foot wide river channel. With no cars around I stopped to see what was happening. Standing in the middle of this very long bridge over this very wide river channel with this one small channel of water I thought out loud, "Shit, I'm in trouble." And so it would be both and understatement and an overstatement.

As I would eventually tell people after I left Arizona, the whole five years was professionally very rewarding and the best thing I did in my career despite being forced to go. But personally it sucked. I hated Phoenix, hated living there, hated the heat, the long hot summers, and hated having to live in air conditioning almost year around. Remember I drove a 1971 VW bug then.

After about two years in the Phoenix office a new technician had arrived and wanted my field trip (upper Salt River and adjacent basins) and I had managed to anger the lead technician, so he switched our field trips. I got his which was the northwest desert. It started just outside Sun City and went to Wikieup. It was a scheduled once or twice monthly trip so the first week of every month I was on the road 5 days the first week and 2-3 days the third week.

The trip has a diversity of gages, rivers and roads into them. And I had to address the one thing I really hated about desert. Critters. Like rattle snakes, scorpions and spiders. They all love gages. Gages in Arizona are made of thick steel to prevent damage from survivalist and hunters with high powered rifles and handguns, and who love to shoot gages. So the gages heat up during the day for critters to live inside.

Well, my two farthest gages were the Big Sandy River near Wikieup and the Santa Maria River near Bagdad. Both were different but similar being big desert rivers.

The Big Sandy River gage as I learned was miles downstream from the bridge I crossed on the way into Phoenix. There were three ways into the gage, all off the highway, but depending on flow and river conditions you forded the river three, one or no places, respectively in order of priority. The two shortest were 2 and a half to 3 hours from Phoenix and the longest 4 hours, one way.

The standard route was the turn off the highway to dirt road that eventually forded the Big Sandy River three times, the last ford about mile where you turn off onto an semi-road sand path to the river. From there you hike about a half mile upstream. And there, bolted with braces attached to a rock wall was a 40-foot high stilling well. The cable way was at the gage where during high flows you hiked to the left bank platform to use it to cross the river to the gage and make a measurements.

I never had to do that except to ride and inspect it once a year. The flow was always low enough to wade to the gage and measure the flow. The real problems were after storms. The locals kept the first two fords solid, meaning packed and graded so hard sand so cars can drive over them with only about 6-12 inches of water. The flow isn't sufficient to undo the hard packed sand.

But it usually took them a few weeks to do this, so the second choice was the road with the last common ford. Except this ford was rarely graded and packed. The local person charged with this didn't like doing it so often, even when the grader was parked right there. So, you had to gamble it would be driveable because it's an hour drive off the highway to the ford - and only a few minutes to the gage, and if it wasn't driveable, you were stuck going back and taking the last choice.

Except if you had the fortitude to risk driving across it. I only did this once, as it was a lesson in what not to do. The storm had eroded the opposite bank of the ford almost nearly vertical. After checking the stability of the sand I thought it's doablel in four wheel low, in granny gear and never stopping - as I was told and taught by folks there. Well it worked until I hit the other side and slammed into it where the front of the truck lifted up and scraped the whole underside on the bank climbing out.

It worked and it worked driving out too except a month later when the clutch was discovered to have been destroyed by sand and water getting in a vent hole Dodge built into their trucks. Talk about stupid. They don't use a plug but an open hole where sand got into from the bank. My boss only said, "Next time, be a little more careful." He told the grumbling mechanics it's part of the work.

The last choice was to drive to Wikieup, turn left and follow the road long on the very long 2 hour drive on dirt and sand backroads to the gage. You often felt you were driving to the end of the world. It was also this road I got my brand new Dodge truck totally off the ground. I was driving down a one lane sand road with 4 foot banks and hit a bump at 45 mph, and suddenly the truck was off the ground and then thumped back down. I slowed down. After breaking my old truck which was due to be turned in anyway - and why my boss excused me, I didn't want to explain breaking my new truck.

When you finished it was a short drive to the last ford to check if it was driveable, and help get out quicker, and if not, you drive back around to Wikieup again to rejoin the highway. And I'll say Wikieup is just a wide spot in the road, nothing to write home, or here, about so leaving there the next stop of Wickenburg or farther Phoenix.

The Santa Maria River gage was similar to the Big Sandy gage, both being standard big desert river gages, and the trip was similar, being long dirt and sand backroads to the parking spot and a walk up to the gage. But it was different in that there were no fords of the river until you got to the parking spot. And there everything was different.

Where the Big Sandy River was easy to wade and measure, the Santa Maria River is a nightmare where you learn to feel the river bed for soft sand and quicksand. You had to wade a 300 foot wide channel usually full of water at or just below the surface of the sand with a smaller stream wandering around, so solid was relative as you used the wading rod to feel a foot or two in front of you.

You would take a step, feel with the wading rod feeling for solid sand, and if it wasn't, the rod would start sinking, maybe a few inches or maybe a few feet. You had to do this for 300 feet to the other side winding your way across, then hike a mile to the gage, and do the same at the gage for the wading measurement. But here is where the two gages were different.

The Big Sandy River gage was at a rock outcrop face, like the Santa Maria gage, but at the Big Sandy the contol below the river was bedrock along with much of the channel for some distance, so finding good footing in the river channel was easy. At the Santa Maria, there was no bedrock on or near the surface, but 50-100 feet below with a huge cross-section of water-filled sand. Hence the quicksand.

The only advantage at the Santa Maria gage versus the crossing point at the parking spot was the some of the sand in the channel was dried out to be solid for walking. But that also meant the gage wasn't connected to the real flow, so you had to dig a small ditch 50-100 feet to get water to the gage to get or check the stage, especially after storm events which deposited a few feet of sand in the stilling well and you had to dig out to get the float back to the river level.

And the Santa Maria River was where I did have to make a cableway measurement. It was one of, if not the, worst cableway measurement I've ever made. I hiked up the river bank to the cable car - we kept one on each side to ensure you always had access to the gage from either side. The river was flowing the entire width of the channel, all 300 or more feet, and was clear as gritty chocolat milk, so you couldn't see below the surface let alone the bottom.

All you saw was sand filled water flowing 3-5 feet per second. In the end it was a bad measurement because the water was only 1-2 feet deep, bad for cable measurements, but the bottom was constantly moving, which meant a wading measurement would have only resulted in my sinking into the channel. There are techniques for sensing the real river bottom during moving beds, so the measurement was ok, just not great.

In the end, after about 18 months with this field trip, being transferred to another one and eventually to project work, my best times were after the work at the gages where I was only driving out. I could take the time to see the desert, even the one time it snowed in December. The whole desert covered with a little coat of white. At the highest point of the drive, I just stopped and stood on the truck to get the whole panorama.

When I left Arizona I drove the same highway out, and stopped at the bridge over the Big Sandy River and said, "Well, trouble or not, it was ok. But I won't volunteer to come back either." And waved goodbye to desert hydrology.

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