Disappearing Rio Grande

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Why Follow the Rio Grande

by Colin McDonald | Feb. 11, 2015

The Rio Grande is disappearing. Demand for water is growing as snow packs shrink, rain patterns shift and average temperatures rise faster than they ever have in the past 11,000 years.

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Dammed River, Day 14

An aerial view shows the diversion dam for the McDonald Ditch, one of many small dams on the Rio Grande that allows water to flow into irrigation canals. This winter the dam will be replaced with a pipe and new rock work that will allow fish to move up and down the river. Photo by: Erich Schlegel

I spent eight hours in my kayak today paddling from Del Norte to the outskirts of Alamosa. It is a 40-mile reach and I did not have much time to spare, but I also did not have much choice.  If I got out of my boat and touched the banks or bottom of the river, I would be trespassing.

In those eight hours, I ran about the same number of diversion dams.  Usually built of boulders dumped into the river, these dams force the river to pool up against the head gates of irrigation canals.

Some of the dams along the Rio Grande here in the San Luis Valley have been around since the late 1800s. A few have been modernized with rebar and cement, but most seem to rely on the pile of rocks model.

All of them add a bit of excitement to paddling. Unlike natural features in a river that are somewhat predictable because of the terrain and geology around them, each of the diversion dams is as unique as the farmer, rancher or company that built it.

You never know when a random piece of rebar could be hidden by a wave, where the rest of the car frame may be or just how deep the swirling water really is.  Fortunately, the dams are rarely higher than six feet, so no matter what is hidden by the whitewater, it is a very quick drop and usually there is an obvious line to take.

Today it was nice that the river was still high, which gave me a little more clearance over the riprap.

The dams and the private-property rights are the biggest hindrance for paddling this reach. But because agriculture is king and the dams have been around for more than a century, the work to make them easier for fish and people to navigate is slow.

Erich and El Burrito are back in Texas for a bit of retooling and repair and will rejoin this expedition once we cross the state line.

I was fortunate to have a local rancher allow me to camp on his land next to the river.  Tonight I go to sleep listening to the herd of cows across the river and the whine of mosquitos trying to get inside my tent.

(Note: My pH and conductivity meter is broken, so the measurements for those two data points are not accurate.)

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Air temperature (°C)
Conductivity (µS/cm)
Depth of Measurement (meters)
Dissolved oxygen (mg/L)
E. coli colonies per 100 ml
pH level
Secchi disk transparency (meters)
Water temperature (°C)

What do these numbers mean?

As they travel, Colin and Erich are taking water samples for the following periodic water quality tests. In partnership with The Meadows Center for Water and the Environment’s Texas Stream Team Program at Texas State University, the results will be added to a public database it helps maintain for research and monitoring water quality.

Air/Water Temperature
Temperature impacts everything from the amount of oxygen in the water and the metabolism of aquatic species to how easily compounds dissolve. Most species can tolerate slow seasonal changes but can go into thermal stress or shock when temperatures change by more than one or two degrees Celsius in 24 hours.
pH Level
The pH scale measures water’s acidity and runs on a logarithmic scale from 1.0 to 14.0, with 7.0 considered neutral. Anything below 7 is acidic and anything above is basic. A pH range of 6.5 to 8.2 is optimal for most organisms.
Dissolved Oxygen
Oxygen is just as vital for life below the surface as it is above. The amount needed varies according to species and stage of life, but generally 5.0 to 6.0 milligrams per liter is required for growth and activity. Levels bellow 3.0 mg/L are stressful to most fish species and levels below 2.0 mg/L for an extended period of time will cause fish kills.
Conductivity levels depend mainly on how easily the rocks and soils a stream passes through dissolve. For example, high levels of conductivity are often found with water that passes through limestone and gypsum because it will pick up the calcium, carbonate and sulfate from those rock formations. However, discharges into a water body, such as a failing sewage system, can also raise the conductivity because of the presence of chloride, phosphate and nitrate.
Water Clarity
Turbid water can come from high levels of sediment or plankton. Both will block sunlight to aquatic plants and the sediments can carry pollution such as nutrients and pesticides. Low levels of turbidity may indicate a healthy and well-functioning ecosystem. High levels can be an indicator of runoff from eroding soils or blooms of microscopic plankton due to high levels of nutrients.
E. coli
E. coli bacteria are found in the colon of warm-blooded animals. If the pathogen is found in water it’s an indicator that fecal mater from humans, pets, livestock or wildlife is also present and may pose a public health threat. For drinking water the standard is to have no E. coli. But almost all non-treated water has some E. coli in it and at low levels it does not represent a substantial health threat to those who swim or wade in it. The Environmental Protection Agency has set the water quality standard for these types of activities at 126 colony forming units per 100 mL.
Secchi disk transparency
The Secchi disk is a plain white, circular disk used to measure water transparency in bodies of water. It is lowered into the water of a lake or other water body until it can be no longer seen. This depth of disappearance, called the Secchi disk transparency, is a conventional measure of the transparency of the water.

While making his way to the Gulf of Mexico, Colin will be periodically activating a device that uses satellite technology to share his current location. Use this map to see where he traveled on this day.

Check-In Time of Check-In (CST) Latitude Longitude
#1 9:53 a.m. 37.6871 -106.35663
#2 11:21 a.m. 37.65965 -106.27081
#3 11:45 a.m. 37.6553 -106.24973
#4 1:47 p.m. 37.60303 -106.13379
#5 3:00 p.m. 37.57447 -106.0672
#6 3:58 p.m. 37.56445 -106.02441
#7 5:18 p.m. 37.56506 -105.97449
#8 6:35 p.m. 37.53095 -105.94743


To report on and understand the haphazard irrigation system the Rio Grande has become and the changes it is going through, Colin decided the best approach would be to travel the length of the Rio Grande by foot and small boat.

He knew it would give him a unique perspective on a river that few understand. It did require many long days of moving slowly and camping on muddy riverbanks, but Colin likes that sort of thing.

The benefit was it provided access to people who wanted to share their stories and experiences with the Rio Grande. Via Facebook and chance encounters, Colin made instant friends who opened their homes. They provided help from loaning their trucks to their cell phone contact lists to help tell the story of the Rio Grande.

The trip would not have been possible without their help, along with the dedicated assistance of David Lozano, Jason Jones and Daniel Dibona, who drove thousands of miles to get people and boats in place.


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