As the dominant terrestrial species on this planet we naturally have a rather grounded perspective of our environment; we named our home planet Earth despite the fact that about 70% of its surface is now covered by water.
On Saturday Sept. 15th 2018, 12 members of the Louisiana Master Naturalists Northeast chapter learned more about the crucial relationship between earth and water in a workshop on Watershed Dynamics organized by our Chair, Dr. Bette Kauffman Professor Emeritus of ULM and very capably delivered by Dr. Bill Patterson, as Associate Professor of Forest Soils and Watershed Management at Louisiana Tech University he was the ideal instructor! I learned a lot from the event, facilitated by Bill’s clear and well-articulated presentation and I also greatly enjoyed the fellowship and conversations with these good people.
Shortly before 09.00 we gathered at Louisiana Tech University’s Reese Hall for the sixth workshop event. We met Prof. Patterson unloading a series of boxes of scientific equipment from a sleek minibus and accompanied him to the classroom for a very comprehensive, illustrated presentation and discussion. An excellent introduction to the sbject, If I may say it.
He began with a basic introduction to the concept of a watershed, defining the term as any area of land that drains water into lakes and rivers.
Watersheds are crucially important sources of clean freshwater. We learned about how relatively scarce and precious, clean, fresh, liquid water is on planet Earth, that less than 2.5% of our water is fresh and that of that small subset, 68.7% is locked up in glaciers and pack ice. Very little of the remaining surface water is clean enough to be potable and so groundwater is very, very important. Here in northern Louisiana we are blessed with, and dependent upon the Sparta aquifer — a pressurized body of fresh groundwater which overlays ‘fossil’ saltwater from our marine pre-history.
Under normal conditions, our planet’s freshwater is a renewable resource in a constant process of refreshment through the hydrological cycle of precipitation and condensation (fog, rain, sleet, hail and snow) and evapotranspiration which is the return of water back into the atmosphere from atmospheric heating and through plants.
Prof. Patterson systematically introduced the concepts of patterns of orographic and convective precipitation, infiltration and percolation, groundwater, and runoff and streamflow. How storm flow builds, peaks and ebbs, and how land use factors affect watersheds. In order of declining suitability: forests are the best groundcover for watersheds, followed by pasture, then row crops and finally urban development.
We learned that the forest soil to the northwest of the Twin cities, in Webster, Bienville and Winn Parishes with its natural mixture of invertebrate life, bacteria, fungi, underlain with porous sandy soil makes an excellent watershed to feed the Sparta aquifer. Two thirds of our drinking water is organically filtered through forest.
We learned that 15-20 years ago the Twin cities’ industrial and commercial activities used more water than domestic households, but now domestic use exceeds industrial use.
We learned of climate change in terms of more severe weather systems, unpredictable seasonal swings of droughts (like July 5 through October 15th 2016) and increased rainfall (March 13th 2017 21.5 inches in 24 hours) but an overall drying that is spreading eastwards from central Texas and points north. Climate is changing, and it is doing so in unpredictable and complicated ways. Healthy forests maintain watersheds that improve our overall resilience.
We also learned that withdrawal from Sparta is currently exceeding the natural rate of replenishment and as a result our water table in Monroe has dropped about four feet and is falling at a rate of 1.8 inches per year. So, it’s probably a good idea for households to consider re-using water responsibly and perhaps using more rain water for gardens and possibly greywater in cases where non-food plants need watering.
We discussed the tension between the planners’ need to prevent standing water accumulation in urban areas to control mosquito borne illnesses and the ecological need to retain water in soil rather than just drain it off. Incorporation of swales that create underground lenses of water within the soil seem good.
After a brief coffee break with thanks to Jennifer, the subject turned to description of methods used to measure streamflow and water quality.
I was very interested to see how scientists measure stream flow with a specific formula that can be applied with equal suitability to areas varying from the size of a drainage ditch to the mighty Mississippi! Where Q stands for quantity, V for velocity and A the cross-section area of discharge, then Q = VA.
Water can be studied at culverts, with pre-designed metal chutes (flumes) and even in stream beds by dividing the area into rectangles and triangles with known measurements and combining these distinct areas to ascertain the total area for the formula to be applied. Dr. Patterson showed us instrumentation and sampling equipment including an extendable current meter, an oxygen monitor with thermometer and measuring kits for specific pollutants like nitrates and phosphate.
Water quality factors include the dissolved oxygen, turbidity, temperature, phosphate, nitrate and nitrite, and ammonia. Tests for gender-bending endocrine disruptors or other chemical pollutants are possible, but are more specialist and expensive.
Some of these water quality factors interplay, for example:
- water temperature and dissolved oxygen levels are related. Cooler water holds more oxygen, warmer water holds less.
- Nitrates and oxygen are related in the way that excess nitrogen boosts plant growth which booms in algal blooms that then die and rot, consuming available oxygen, reducing dissolved oxygen to dangerously low levels that are lethal to fish and other gilled organisms.
- Turbidity leads to higher temperatures because the sediment particles absorb more solar radiation than pure water alone can do. Excess sediment can choke fish and invertebrate eggs and block plants’ ability to photosynthesize starch from sunlight and carbon dioxide.
He showed us a Google Map of the Redwine Creek with study stations marked. The lower measuring station in land owned by Weyerhauser that was formerly granted the status of Wildlife Management Area is no longer accessible unfortunately. The creek supplies water to The Dugdemona river which in turn runs into the Red river which feeds the massive Atchafalaya wetlands, a huge wildlife-rich area approximately the size of Wales. An ecological jewel.
We would visit two of the study stations after lunch to sample the water quality and stream life. The first was on Grambling University grounds, accessed from Facilities Road.
Dr. Patterson arranged a Tech van to take us to the stream; some members drove independently. We disembarked at Redwine Creek in Grambling, La. Members helped carry equipment down to the stream.
First, we measured the discharge (streamflow), temperature, turbidity and dissolved oxygen level. Members with waders gamely waded out to the culverts for sampling, others used dipnets and Dr. Patterson and Kalem Dartez cast a weighted castnet, both had good style! Betty and Suzanne used a seine net in tandem. Kimmie photographed a fast moving Southern Broad-banded Watersnake. Nobody fell in, but you can see from the data that we wouldn’t have contracted a cold or pneumonia from the warm water if any of us had taken a dip.
Redwine Creek North
Turbidity: 74.55 NTU
Dissolved Oxygen: 7.20 DO
Temperature: 27.3°C / 81.14°F
On May 1st 2018 students had recorded the turbidity at 41.8 NTU, temperature as 18.5°C and Dissolved Oxygen as 8.9 so we were able to determine that water conditions had changed with regard to these factors and their quality at this station can be considered impaired. Even so, there was healthy-looking aquatic life in the form of two species of fish, a watersnake and two crawfish.
Afterwards we noted that soil disturbance on the banks would be at least partially responsible for the increased turbidity, it would be good to look into turbidity amelioration on that stretch.
We observed the following wildlife:
River birch, Betula nigra
Peppervine, Ampelopsis arborea
Slender spike grass, Chasmanthium laxum
Bordered plant bug, Largus californicus
Lovebug, Plecia nearctica
American crow, Corvus brachyrhynchos
Black vulture, Coragyps atratus
Carolina wren, Thryothorus ludovicianus
Fish crow, Corvus ossifragus
Northern mockingbird, Mimus polyglottos
Red-tailed hawk, Buteo jamaicensis
White-eyed vireo, Vireo griseus
Reptiles and Amphibians
Broad banded water snake, Nerodia fasciata confluens
Puffball mushroom, Basidiomycota sp.
“Red-finned” Shiner, Notropis cornutis
Western mosquitofish, Gambusia affinis
2 Crawfish, Astacoidea sp.
We re-boarded the van and visited the second station where the river has passed through a water treatment plant and actually falls in a small cascade over a concrete step just past the bridge. Here the turbidity had dropped by 30.79 NTU. Dr. Patterson also conducted a Phosphate test which showed the level to be impaired.
Here are the notes from the lower station:
Redwine Creek South
Turbidity: 43.76 NTU
Dissolved Oxygen: 7.36 DO
Temperature: 27.6°C / 81.68°F
All the above figures show impairment.
Goldenrod, Asteraceae sp.
Virginia Wildrice, Poaceae sp.
Amberwing, Perithemis sp.
Lovebug, Plecia nearctica
Damselfly (green stripes on thorax, blue band on tail)
Dragonflies, Odonata sp.
Damselfly Naiad, Odonata sp.
Dragonfly Naiad, Odonata sp.
Black vulture, Coragyps atratus
Blue jay, Cyanocitta cristata
Northern cardinal, Cardinalis cardinalis
I am very grateful to everybody who cast their eyes about looking for the rubber eye-cup that fell off my camera’s new LCD panel loupe* near the second station. My thanks to Jeff Barnhill for finding it and getting it back to me.
From the conversations in the minibus it was clear that members enjoyed the event and found it very interesting and stimulating, Kimmie and I certainly did too.
Water is very much a part of life in northeastern Louisiana and we are never far from a water body of some sort. Some of our members live right by the Mississippi, others near Bayou D’Arbonne, and others Cheniere Lake. For our own part, we feel fortunate to have springs from the Sparta aquifer at the bottom of our land near Farmerville and so all of this seemed particularly interesting to us.
This is my first draft of the account, it is likely to be improved by the peer review process, so you can expect some revision.
*A note on LCD Loupes
I think they’re a brilliant accessory. Recently I’ve been aware of missed focus on some of my pictures and I have always had difficulty in bright sunlight seeing details on my cameras’ rear LCDs. I bought an LCD Loupe for about $70 inc. tax postage etc. last week and feel that it has helped a lot! The unit is about 10cm long and has a diopter adjustment ring and a rubber eyecup that you can use for either eye, that hugs your cheek. Watch out that you don’t knock off your eye-cup with the camera strap. It might be worth keeping that in a pocket and just applying it when you’re ready to shoot. It works pretty well without the eye-cup, but this extra friction on the cheek helps stabilize the camera nicely too which means you can knock back that ISO for cleaner images with more detail.
I don’t know about you, but I find any steadying effect is useful in wildlife photography because the more excited I am about my subject, the more likely I am to spoil a picture in borderline conditions through camera shake. How often the great shots are in lower light. What a pain to blur the special opportunities! Or be forced to use a high ISO to ensure a suitably fast shutter speed and appropriate depth of field. My cameras all have image stabilization in the lenses, bodies or both, but the steadier I can hold the camera the better.
The unit works in addition to the quick release plate on my Vivitar tripod, so I can have both on at the same time. You can adjust the placement with the side-knobs and flip up the magnifying optic to put it out of the way if you want to view the LCD screen unmagnified. In short, it’s like having a better viewfinder. OK, so you’ll use your camera battery up faster than if you just use the viewfinder, but that’s a penalty I’m prepared to accept for getting that line of finest focus where I want it, more of the time, very handy with a 50mm F1.4 and with macro lenses.
NB. C. Paxton’s endorsements are genuine, personal opinions, he was not paid to express them on this blog.