Salinity levels are rising. Brown pelicans are becoming common. We are getting very close to the Gulf of Mexico.

There are 12.9 miles of Rio Grande left, but we are saving it for Friday so others can join us. We are also hoping the next batch of wind and rain will blow itself out by then.

It should be an interesting paddle.

We have passed the last of the levees and the nature of the river is changing. The banks are 5-feet high instead of 20 and made more of sand than mud. We can see jack-up oil rigs and sand dunes. There are blue crabs scurrying along the bottom of the river and locals are starting to warn us less about alligators and more about sharks. So far we have seen neither.

What we did see today was dozens of gill nets stretched across the river. The gaps of the monofilament nets range from two to five inches.

Judging by the amount of trash in the nets and the film growing on them, it seems some have been set out for months. These nets held decaying fish. Other nets were being actively worked by men using everything from traditional high-bowed skiffs to the shells of jet skis.

We saw one net that stopped near the middle of the river, the official boundary between the United States and Mexico. The rest were anchored to each shore.

We wondered how any fish could survive. Judging by the number of egrets, herons, ospreys and pelicans, there must be a fair number to go around.

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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: 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.

Check-In	Time of Check-In (CST)	Latitude	Longitude
#1	8:21 a.m.	25.85022	-97.3985
#2	9:54 a.m.	25.85118	-97.36423
#3	10:39 a.m.	25.86095	-97.36767
#4	4:30 p.m.	25.93542	-97.2771
#5	5:11 p.m.	25.94792	-97.28125

About

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.

Disappearing Rio Grande

Why Follow the Rio Grande

Jan. 20, 2015

Getting Close, Day 216

Photos #

Measurements #

What do these numbers mean?

Check-ins #