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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Crossing Amistad, Day 169

A bobcat looks down from the limestone cliffs of Mexico that line much of the Lake Amistad shoreline. Photo by: Mike Kane

 Last night, as we paddled against a dying headwind looking for a campsite, Mike thought he heard a chicken. Then he saw something move on the cliffs to his right. 

We never found out what made the chicken sound, but we saw a bobcat climbing up the cliffs into Mexico. 

The cat did not seem to mind when we paddled over to get a closer look. It gazed down from 20 feet above the water and seemed it could not care less as we admired its white coat with black spots and streaks. But it did give us several different poses.

Then we saw a second bobcat, this one with orange and white markings, like a small tiger. It also posed for us in a nonchalant manner, giving us both profile and straight on eye contact. After the four-minute photo shoot, the cats wandered away from the cliff edge.

It’s how things go on Amistad. Nothing stays for long.

Amistad Reservoir is famous for bass fishing and small-craft warnings. Both result in dangerous conditions for canoes. 

The bass fishermen prefer high-speed motorboats with long, flat decks.  They kick out a short, steep wake and from the water it is very difficult to tell if the driver sees you or not as they skip over the water at 40 mph. 

The southeast winds push up 4-foot high waves in the open reaches of the lake that are ideal for swamping small boats.  

Such conditions make canoes rare on the reservoir. People who do paddle tell stories of hugging the shoreline, making the crossing twice or three times as long. Others end up going even slower as they wade the rocky beaches while towing their boats.

We had none of that. We launched at 7:30 a.m. onto water that was as flat as glass and paddled directly into a fog bank. A light westerly wind picked up behind us and we skipped from point to point, never quite leaving the sight of land, but never really being sure where it was. We navigated by map and compass and listened for the whine of approaching motorboats.

We made as many miles as we could, taking only one mid-morning break. We were worried that at any moment the wind would shift and we would be stuck.   

Instead the fog lifted and the tailwind gained strength.

We flew across the lake. By lunchtime we had made 18 miles and were paddling up to Amistad Dam. It was a huge relief and I smiled like a fool. I thought we were going to be stuck on the lake until Monday.  

I’m sure the bobcats were not impressed.

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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 6:30 a.m. 29.55677 -101.24789
#2 10:14 a.m. 29.49074 -101.15845
#3 12:16 p.m. 29.46171 -101.06763
#4 4:33 p.m. 29.425 -101.04102
#5 6:12 p.m. 29.37786 -101.01331


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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