Saturday, 9 September 2017

"Don't Know Much About Hydrology..."

"Don't Know Much About Hydrology..."

Posted on September 22, 2013 at 2:00 PM
"Don't know much about history
Don't know much biology
Don't know much about a science book..."
(Sam Cooke lyrics: "Wonderful World")

Drainage Pattern map of Mountain View wetland and upland area

As of 2011,

"Knowledge of runoff processes and hydrologic response is essential to understanding the role of wetlands within the larger environment.Small forested swamps are common in Coastal Western Hemlock (CWH) forests and represent an important habitat for birds, amphibians and larger mammals. However, hydrologic processes that generate runoff in these mineral wetlands are not completely understood."

Is the achievement of sustainable management for vernal pools or any other landscape or resource a reasonable near-future objective? Our history, as a species, of attaining sustainable management is dismal. A few years ago the ecologist Donald Ludwig, of the University of British Columbia, wrote an essay entitled “Environmental sustainability: magic, science, and religion in natural resource management. His historical review of human failure to achieve sustainability even in the ecosystems humans know best—forests, farms, fisheries—led him to rhetorically ask how we can now think that sustainable management of less well-known ecosystems is within our grasp. “Science is founded upon the conviction that experience, effort, and reason are valid; magic on the belief that hope cannot fail nor desire deceive.” He concluded that our current expectation of achieving sustainable resource management is based more in magic than it is in science.

Like the biota in any ecosystem, vernal pool plants, animals, and microbes have co-evolved with each other and in relation to narrow environmental conditions. The complex result is rather difficult to imitate in humanly created pools. Our attempts to move and create vernal pool ecosystems have only been partially successful, as presentations in this conference attest, and even this measure of success is based on short-term observations of half a dozen years or less.

The successful retention of a diverse suite of organisms can probably best be judged by monitoring over a time period long enough to include the historic, natural range of environmental variability (drought years, wet years, cold years, warm years). For vernal pools, this period of time might well exceed a decade. For ecosystem types which have longer-lived woody plants or vertebrate animals, the necessary period of monitoring might well exceed several decades and even approach a century…Is such long-term monitoring and management possible? Do we have the kind of social infrastructure that could maintain consistent policy and monitoring plans for that length of time? Do we, as a species, have decade-long to century-long attention spans?

I personally imagine that the answers to those questions are “no.” Until the answers can be “yes,” the prudent, conservative policy should be to retain as many vernal pools and as much of the natural landscape as we can, while attempting mitigation, enhancement, and restoration activities at the same time.
 ~Michael G. Barbour

As we have noted, mountain bike trail building is full  of "drainage mitigation" work without having a clue/care?  about the hydrology of the area they are digging around in. The complete understanding of how hydrology works is still in its infancy. But one thing for sure: "Mountain bikers mess up acquifers", like they have done to the area in the upland where LowerGriffen Switchback, Upper Griffen, Natural High, Immonator Trails converge... Mountain bikers tend to hold a very cavalier attitude toward the environment.

Back in the early 1970's there was an innate understanding that hydrological processes in the lowland and upland area shouldn't be tampered with. But much damage has happened since this initial report, mainly due to the indiscriminate riding and trail building by mountain bikers. DNV public land managers have pretty much ignored the good advice of the "Twin Lakes Development Study" (1970):

The Mountain View area is located on the northern fringe of the Fraser River Lowland, within the western system of the Cordilleran Physiographic Region. It occupies one of the Lynn Creek terraces south of the Pacific Ranges of the Coast Mountain Region. The lowland area is at 750 feet above sea level, and a small scale  stream channel courses through, emptying into the pond.

In contrast, the escarpment on the west side of the pond site rises sharply to about 800 feet above sea level before levelling off on the top of am upper terrace. Similar conditions exist along the eastern fringe where the land drops rapidly to the base of the lower terrace. The study spoke of the importance of the northwestern scarp, and that it should not to be developed, but remain a natural area.  Damage to this higher topography would result in serious ecological and physical implications, the study stated.

But, the surface areas have already been damaged by much erosion and compaction due to indiscriminate recreational use of the area (mainly mountain biking).  The surface area was characterized by a peaty overburden made of of partly decomposed organic matter, which varied in thickness from 6 to 10 inches.Because the materials below are very well drained, from continuous leaching during the rainy season (sandy in texture - classified as loamy sands, stony to very stony), the surface area plays a major role in absorbing and retaining the natural water supply of the site (aquifer). In addition the composed organic matter also forms a protective mat against erosion, a factor which is significant in view of some of the steep slopes and rainfall in the area. This organic matter has since been removed, and the ground compacted, and eroded, in much of the area.

So what do we know about Drainage and Groundwater patterns of the area (circa 1970)?
(see the "Drainage Pattern"  map, above)

Surface water from the western scarp runs down the steep slopes where it quickly diappears in the porous soils on the lowland (much of this soil had become heavily compacted around the pond area and south of the Baden Powell Trail, due to recreational overuse). A limited amount of water flows along a few small defined channels. These channels may periodically come into spate as streams, but in a short while appear to be dry (ephemeral).

It was recommended that the aquifer (western slopes), aquifer recharge areas (surface and subsurface drainage channels) should have become the entire park area. And that the park area remained a natural environment. Design and management criteria was outlined in the study to preserve the natural character of the area. Much of this advice was disregarded by DNV once the mountain bikers/NSMBA flexed their political muscles  to ride and build inside the area, and elsewhere on Fromme Mountain:
"For more than two decades, mountain bikers were creating trails on the North Shore without the permission of municipal officials. The District of North Vancouver has created a process to determine which trails should remain in place for mountain bikers, which should be termed "multi-use", which should be exclusive to hikers, and which should be decommissioned. District of North Vancouver mayor Richard Walton, a trail rider himself, describes mountain biking as a "legitimate" land use..."
(The fact is, DNV has yet to follow through with many trail closure proposals. Instead, we have seen too many new trails being built where they should not have been, especially  down the sensitive escarpment slope... but they did, because of the mountain bikers' and the Mayor's "political clout". There is no other reason. Mountain biking organizations like the NSMBA can only gain as much "political muscle" as the public land managers and politicians are willing to give them. No more, no less!)

Instead of the proposed boardwalk, with amphibian tunnels, DNV fragmented  habitat by running a gravel path through the park.  Mountain bikers have succeeded in eroding that pathway, and will succeed with doing so with the newly resurfaced gravel path, once again, as long as they continue to ride in the area.) "Recreation Before Conservation", seems to be the motto of DNV and many environmental organizations, today.

There are some kinds of recreation that are inappropriate for certain natural areas. Offroad vehicles of any kind do not belong in this wetland area. Mountain View Park wetland and upland area should be changed to a "Limited Mountain Recreation Zone", which effectively bans mountain biking inside it --- along with more trail closure, especially on the steeply sloped escarpment. Pursuits like hiking and passive nature walking, etc. would put a much lesser footprint on the urban wetland area. Mountain bikers are always trying to divert drainage patterns, and plug up seeps and small vernal pools on their trails, without restraint. 

Wildfire mitigation (vegetation management) plans (2014) for Mountain View Park may be more detrimental to the park, than helpful, in light of the 1970 hydrological study of the area. The area proposed for "management" is relatively pristine, and a thriving swamp habitat for many small wildlife. This swampy area is full of water- filled  depressions and seeps that should not be disturbed.
It is far wiser not to try to "manage" something we do not fully understand. Unlike the BC interior where wildfire interface mitigation may work, the ecology of this area is vastly different. Any attempted vegetation removal from this relatively pristine "swampy complex" would  most likely have the detrimental effect of drying the area out even more. This is only common sense "science" :                                                                                                                                                     

(Photo, below: Typical NSMBA volunteer trail work in progress, during the pouring rain, on Fromme Mountain.)

"La ta ta ta ta ta ta (History)
Hmm-mm-mm (Biology)
La ta ta ta ta ta ta (Science book)..."

More information about hydrology and wetlands:

Hydrologic response of a small forested swamp complex, Seymour Valley, British Columbia

Conserving Biodiversity in Greater Vancouver: Fact Sheet #1 – Wetland Ecosystems

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