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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The Changing River, Day 172

After giving a friendly wave, a man in Acuña watches as Colin and Mike paddle the Rio Grande. Photo by: Mike Kane

We paddled into Del Rio on a river where we could see turtles swimming among the rocks on the bottom. Now, 15 miles south and several discharge pipes and questionable streams later, we can no longer see the bottom. The smell of sewage comes and goes as the current mixes the water and we think twice every time we step out of the canoe.    

Rumaldo Sandoval owns a ranch a few miles south of Acuña and we talked to him while he fished from the Mexican bank. The only people we saw on the river were on the Mexican side. Almost everyone returned our wave and happily talked about how they were spending their Sunday along the river.  

Sandoval was fishing and taking in the view with his wife, Maria Gonzalez, and dog Osa.  

He called the discharges black water. We could see where it tainted the river from a clear blue to a teabag brown. The river sediment has a thin layer of brown on top and then a thick layer of black goo.  

Sandoval said he would not drink from the river, but in the summer it is a great place to swim.  

And it’s much safer now. When he was a little boy, the flood of 1954 swept through the valley. He knew people who had to run uphill and wade through chest-deep water to escape the rising river. Entire communities were wiped out and had to resettle.   

The flood prompted the construction of Amistad Dam, where Sandoval worked for eight years in the electric plant. He now works making parts for Jeep Wranglers and Dodge Durangos.   

Now we are at the second dam, a diversion for the Maverick County Water Conservation Improvement District No. 1. It looks like it is taking about two-thirds of the river, which will be sent off to irrigate pecan orchards and farms before flowing back into the river. 

In between the here and there, we will just have to make due.   

The border patrol agents and dam operators we spoke with told us we will likely have to haul the canoe over rocks on several upcoming sections.  

But at least we will have company.   

The birds, especially the coots, are here by the thousands. Camping on an island felt like being at an airport with no traffic control. It seemed the pelicans, herons, egrets and ducks could not decide where they wanted to be and flocks were constantly landing and taking off.  All through the night, we heard beavers chewing on small trees, smacking their tails and plopping into the river. Meanwhile, flocks of birds jockeyed for position in the air and on the water.  

It was anything but sterile.

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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 8:09 a.m. 29.24047 -100.79471
#2 9:37 a.m. 29.17798 -100.76547
#3 4:20 p.m. 29.15651 -100.75861
#4 7:52 p.m. 29.15601 -100.75677


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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