water

Δ DELTAS

 

Several studies have noted the temporal coincidence between shoreline erosion around some major deltas (e.g., Nile, Mississippi, Ebro), and the reduction of stream sediment loads due to reforestation, soil conservation practices, and trapping of river sediment behind dams. There are, of course, excellent reasons to suspect a causal link, but the link itself has not, in my view, been fully established.

HYDROPEDOLOGY: FLUX-STRUCTURE INTERACTIONS

Subfields such as biogeomorphology, ecohydrology, geoecology, soil geomorphology are areas of overlap between disciplines and subdisciplines. They are governed by the paradigms of the overlapping fields, and fit more or less comfortably within, and at the boundaries of, those fields. They do not have an independent paradigm or conceptual framework (which in no way reduces their importance or vitality).

Landscape ecology, by contrast, has developed its own paradigm—pattern, process, scale—that is independent from mainstream ecology, biogeography, and geospatial analysis.

Does, or can, hydropedology have such an independent paradigm? Is its development best served by, say, the ecohydrology or soil geomorphology model as an overlap field dominated by existing paradigms of pedology and hydrology? Or is a landscape ecology, separate paradigm direction more appropriate?

THE INHERENT EPHEMERALITY OF WETLANDS

As a citizen, an environmentalist, and a scientist, I am absolutely committed to the conservation and preservation of wetlands. The ecosystem services provided by wetlands are immense; their hydrologic, ecologic, economic, and aesthetic values are long since beyond serious question. However, as we strive to protect these inarguably valuable resources, we need to keep one thing in mind—marshes, swamps, bogs, and other wetlands are inherently and irreducibly subject to change.

First, many of them are geologically ephemeral. They are recently formed and very young in geological terms, and under no circumstances would they be expected to remain static—geomorphically, hydrologically, ecologically, or locationally—for very long. The estuaries of the Gulf coast of the U.S., for example—and their associated tidal flats, salt and freshwater marshes, mangrove swamps, freshwater swamps, etc.—were established in approximately their current locations only about 3000 years ago. That’s nothing in geological time. Even at that, both the external boundaries and internal dynamics have been anything but static in that time, and change is ongoing. This kind of youth and dynamism is the rule, not the exception, for wetlands around the world.

ANASTAMOSING CHANNELS

Recently published in Earth Surface Processes & Landforms: Anastamosing Channels in the Lower Neches River Valley, Texas. The abstract is below: 

 

Active and semi-active anastomosing Holocene channels upstream of the delta in the lower valley of the meandering Neches River in southeast Texas represent several morphologically distinct and hydrologically independent channel systems. These appear to have a common origin as multi-thread crevasse channels strongly influenced by antecedent morphology. Levee breaching leads to steeper cross-valley flows toward floodplain basins associated with Pleistocene meander scars, creating multi-thread channels that persist due to additional tributary contributions and ground water inputs. Results are consistent with the notion of plural systems where main channels, tributaries, and sub-channels may have different morphologies and hydrogeomorphic functions. The adjacent Trinity and Sabine Rivers have similar environmental controls, yet the Trinity lacks evidence of extensive anastomosing channels on its floodplain, and those of the Sabine appear to be of different origin. The paper highlights the effects of geographical and historical contingency and hydrological idiosyncrasy.

 

CHANGING LANES

Some form of the diagram below is often used as a pedagogical tool, and to represent a theoretical framework, in fluvial geomorphology, hydrology, and river science. It is called a Lane Diagram, and originated in a publication by E.W. Lane in 1955:

The diagram shows that stream degradation (net erosion and incision) and aggradation (net deposition) responds to changes in the relationship between sediment supply (amount of sediment, Qs, and typical sediment size, D50) and sediment transport capacity (a function of discharge or flow, Qw, and slope, S). The diagram is a very helpful metaphor in understanding the sediment supply vs. transport capacity relationship, and its effects on channel aggradation or degradation.

DYNAMIC EQUILIBRIUM (?) IN RIVERS

Nicholas Pinter, a Southern Illinois University geomorphologist, gave a nice talk yesterday on rivers and flooding in the 21st century as part of UK’s Water Week. Pinter’s talk got me to thinking about the concept of “equilibrium” in environmental systems and what it means to both geoscientists and laypersons. Pinter correctly noted that rivers tend toward dynamic equilibrium, and more specifically, dynamic metastable equilibrium. This means three things: First, the system (river) is more or less constantly changing (the dynamic part). Second, equilibrium is of the type envisioned in mathematics and systems theory—that is, a state or condition the system settles into after a change or perturbation, with no further connotation other than that the response to the change has run its course (I’ve called this “relaxation time equilibrium” in my work). Third, “metastable” means that these equilibrium states are not necessarily stable and self-maintaining, and may be sensitive to future disturbances—even relatively small ones. Pinter’s message is that dynamic equilibrium in rivers means that rivers are constantly changing.

RIVER RESTORATION & REHABILITATION

 

Yesterday I heard a very interesting river restoration workshop at the British Society for Geomorphology meeting. What I’m about to discuss was not the focus of the workshop, but it was triggered by thinking about geomorphology, hydrology, and river science in stream rehabilitation and restoration, which is a big business now.

The stream restoration problem is often portrayed as something like this:

 

That is, the stream is currently in some kind of degraded, suboptimal, unwanted state. The goal is to restore it to a “natural” or some more desired condition, often conceived as whatever the stream was like before the degradation commenced. There are a number of problems with this, one being that in many cases the pre-existing state is not known. Even if it is, since rivers—like other landforms and ecosystems—are dynamic and changeable, there is no particular scientific reason to believe that, in the absence of human-driven changes, the river would still be now as it was decades ago.

International Youth Water Justice Summit

Join the U.K. Appalachian Center for the International Youth Water Justice Summit at Memorial Hall on Saturday, July 12th, 2014 from 9 a.m. to 5 p.m.  This event is free and open to the public; all ages are welcome to attend (children under the age of 16 must be accompanied by a parent or guardian). Lunch will be provided. There will be presentations and activities related to water justice locally, regionally, and globally throughout the day. Water justice refers to fair and inclusive distribution and stewardship of water resources. This is an opportunity to think about how you are connected to everyone in the world through water, from the make-up of the human body to the watersheds providing us with drinking water to the river, ocean, and weather systems that keep water circulating.

Here is the schedule for Saturday's events:

Just outside Memorial Hall (or in the lobby, if raining) will be these hands-on activities through the day:

9-5 Enviroscape (Bluegrass GreenSource)

11-2 Paint your watershed (KY Riverkeeper)

9-5 Meet a salamander (UK Forestry/Appalachian Center)

 

Inside Memorial Hall:

9:00-9:15 Welcome

9:15-10:00 Introduction to the Kentucky River Watershed by the KY Riverkeeper

10:00-11:00 Global discussion of water issues between those in Memorial Hall and young people joining us electronically from Morocco and Turkey

11:00AM-12:00PM Examples of community forestry/water management from Indonesia

12:00-1:00 Outside (weather permitting): lunch; inside: screening of the film THIRST

1:00-1:30 Panel/discussion: participants in the International Youth Water Justice Workshop in the Robinson Forest in Appalachian Kentucky, 7/7-11/14

1:30-2:00 Presentation/discussion: the state of global rivers

2:00-2:15 Break

2:15-2:45 Presentation/discussion: water crises close to home that have and have not made the news, and responses to them

2:45-3:00PM Movement/music

3:00-4:30 Kentucky examples of community-based watershed decision-making and monitoring: Kentucky Water Resources Research Institute

4:30-5:00 Closing discussion

A map for reference can be found here: http://www.uky.edu/pts/sites/www.uky.edu.pts/files/pdfs/ukpts-parking-map-summer-large.pdf. Parking closest to the event site of Memorial Hall includes the Rose Street Parking Structure #2 (located off of University Drive, with access from Hilltop Avenue), lots located off of Rose Street on Funkhouser Drive, and lots located between the Slone Building and the back of the Funkhouser Building off of Washington Avenue (via Gladstone). Please, see the construction plan map below and note that it is subject to change. It may be necessary to park in one of the alternate locations listed above.

For more information please contact Erin Norton, Department Manager at the UK Appalachian Center, 859-257-4852, erin.norton@uky.edu. To learn more in general about the UK Appalachian Center, you can visit our website at appalachiancenter.as.uky.edu/

Date: 
Saturday, July 12, 2014 - 9:00am to 5:00pm
Location: 
Memorial Hall

Working With Water Around The World: Alan Fryar

Alan Fryar of UK’s Department of Earth and Environmental Sciences was recently awarded the prestigious Fulbright Program scholarship by the U.S. Department of State’s Bureau of Educational and Cultural Affairs. Fryar will be studying the influence of climate change on spring flows in Morocco’s Middle Atlas Mountains.

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