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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Sabal palm, Day 215

Max Pons pulls against one of the steel posts of the border fence at the Southmost Preserve. He manages the preserve for the Texas chapter of the Nature Conservancy. Photo by: Colin McDonald

The sabal palm forests and citrus orchards of the Rio Grande Valley feel like home for Max Pons. He has lived and worked among them for most of his life.

“I’m a fifth generation South Texan,” he said. “My great-great-grandfather was a sea captain and a river captain. I’m guessing he was the kind of guy who cut down a lot of things. I’m trying to put some back up.”

Of the estimated 40,000 acres of sabal palm forest that once stretched along the Rio Grande, less than 300 acres exist today. Of that, one of the largest stands is on the 1,034-acre Southmost Preserve, which is owned by the Texas chapter of The Nature Conservancy and managed by Pons.

TNC is a supporter of this project and I am writing this post from my tent inside the packing warehouse of the old orchard.

Pons and his seven neighbors drew national attention when their homes were left on the “outside” of the border wall. The tracks of mud from people climbing over the fence that splits the preserve can be seen on the rusted steel posts that create the 20-foot-high barrier.

The sabal palm forests were cleared to make room for farm fields on the rich soil of the Rio Grande delta. Now the farm fields that are on the preserve help protect the last remaining stand as Pons works to show how conservation of habitat and agriculture can work together.

The water of the Rio Grande is over allocated for use by cities and farms, meaning that there is no water to spare. Even if there was water available, under Texas law, water can’t be dedicated for wildlife. So the only way for Pons to get the water he needs to maintain the moist soils the palms enjoy is to irrigate the surrounding fields. The irrigation runoff is then channeled into drainage ditches and allowed to flow into the wetlands that border the forests.

To take it one more step, Pons is planning to cut down large swaths of the citrus orchards on the preserve. Some palms have naturally planted themselves in the orchard. Until last year, the orchards were in commercial production of organic grapefruits and oranges.

Pons plans to cut them down and allow native plants to repopulate the land.

As the sun set, he walked the rows of trees that he would like to cut and looked for a grapefruit with tight skin and a flat bottom and top.

He wanted one that was what he called “elbow good."

He found what he was looking for and cut a slice for Jessi Loerch, the editor of this project who has come down from Seattle to paddle the last 50 miles, and me.

The bright meat of the fruit burst as soon as we bit in. The sweet juice ran down the length of my forearms. They were elbow good.

Pons smiled and reassured us he is going to leave a couple of rows of both the grapefruits and oranges. He donates the fruit to the zoo and local bird sanctuaries to be used as feed.

And it would just not be the Valley or his home without the citrus trees. 

Expedition update: Along with Jessi, my brother, Ross McDonald, and close family friends Jonathan Hayes and George Hayes have joined the expedition to paddle the last 50 miles to the Gulf.

We are no longer getting accurate readings from the dissolved oxygen meter.

To comment on this post or ask a question, please visit the expedition's Facebook page.

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 10:31 a.m. 25.8903 -97.49692
#2 11:37 a.m. 25.88181 -97.47073
#3 12:37 p.m. 25.87772 -97.45462
#4 1:14 p.m. 25.87703 -97.45489
#5 2:28 p.m. 25.85652 -97.44632
#6 3:41 p.m. 25.85976 -97.40819


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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