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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Cave Fishermen, Day 168

Commercial fishermen from Mexico head out in the evening to check nets on Amistad Reservoir. Photo by: Mike Kane

Juan Martinez started fishing Amistad Reservoir as a boy while helping his father. He liked the work. It was better than the factories.

The downside is the accommodations can be a bit tiring.    

“I’ve lived 15 years in a cave and four days in my house,” Martinez joked in Spanish. 

We had been paddling into a cold headwind for two hours. Our strokes were getting a bit sloppy, the waves were getting bigger and we needed to take a break. When we saw Martinez’s cave, we swung over to say hello and get out of the wind and waves.  

Martinez and his fishing partners, all family members, are on the water Monday through Thursday all year. They use gill nets to pull everything from crappie to catfish out of the lake.  

While they are out at the fish camps, one boat makes daily trips to the dock so the fish can be sold fresh in Acuna. Everyone else camps out in caves that line the lakeshore so they can stay close to the prime fishing grounds.   

The camps are set up with an office chair for the record keeper to sit in while the daily catch is being weighed, a table for cleaning the fish and a freezer that is used as an ice chest. The caves do not come with electricity.   

Beds are foam mats and blankets on top of blue tarps. The kitchen is equipped with a grill above a bed of coals and a barrel of drinking water. The bathroom is outside the cave and accessible via a rope that hangs down the cliff.  

In their open skiffs with four-stroke 50 horsepower engines, the fishermen will go as far up the Rio Grande as lake levels allow to set their nets. Congealed cow blood is used to attract the fish.  

In a good week, a single fisherman can catch 500 kilos of fish, more than half a ton. But that is becoming harder to do, explained Juan Martinez’s father, who goes by the same name. He has been on the lake for 40 years. 

The mud brought in by the Rio Grande and Pecos is filling up all the narrow channels that used to be the best fishing holes. The mud also makes the lake narrower. 

The U.S. confiscates nets that drift across the border. As the head of the lake becomes narrower and shallower, it is now impossible to set a net without risking losing it in many places. The lake is simply not wide enough.   

But there are still enough fish to keep the Martinez family on the lake.   

They warned us the wind would push up steep waves that will knock water into even their high-bowed boats. They offered us a ride. They also offered us hot coffee, fresh fish and a spot by their fire. It was by far the most hospitable cave we have visited.   

We accepted the hot coffee and warmed up by the fire. We did not have a way to cook the fish.  

The wind had calmed down so we decided to head out on our own. If the wind was bad the next day, we would either stay put or flag them down.   

They nodded. Being on the lake is where they want to be, too. 

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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 7:18 a.m. 29.60024 -101.31116
#2 10:15 a.m. 29.57498 -101.29538
#3 2:10 p.m. 29.59008 -101.24487
#4 3:26 p.m. 29.557 -101.24808


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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