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March 25, 2018
Sinkhole discovery In Thundering Waters Forest
Dr. John Bacher
Since 2008 there has been a major battle to protect a 483 acre of diverse native Carolinian habitats in the City of Niagara Falls, well known as the Thundering Waters Forest. Most of these threatened lands have as a result of ecological field work stemming from a mediated Ontario Municipal Board negotiation in 2008, which provided for site access for provincial wetland evaluators, become protected wetlands.
In October 2017 there was announced a smaller 120 acre version of the development proposal, which became known as the Riverfront Community. Most of this is proposed to be built on lands which are not protected wetlands, although the developer has proposed to have some areas reviewed for a Down Rating process based on field observations. Sadly, one of these nine areas, Wetland Number One, has already been Down Rated. This was on the basis of a field investigation which revealed two blocks of concrete that were thought to show human origins of the wetland area. They may have been bridges over a now vanished stream that flowed here Warren Creek.
Google map of Sinkhole location. Robert Hillier.
One of the worst aspects of Riverfront is a proposal for a road in between two blocks of protected wetland. It is half way between the northern edge of the development and the Welland River, it would make wildlife movement very dangerous between what would become two fragmented blocks of now intact forest. In Figure 11 of an Environmental Impact Study, (EIS) by Savanta, it is labeled as “Potential Impact” area 5″.
Page 38 of the EIS warns that, “Impact area 5 is a barrier to the connectivity for reptiles and amphibians moving from the Welland River, internally through the subject land.” This is a polite warning by developer paid ecologists of impending wildlife slaughter.
From walking through the tiny gap between two blocks of protected wetlands where the east west road through the heart of the Thundering Waters Forest like a dagger is planned, I soon discovered why it is not classified as a wetland. To be considered a wetland at least 51 per cent of the plant species present must be those that favour wet conditions.
The gap in the continually forested landscape of protective wetland designations is caused by a significant hydro geological feature. The proposed east west road’s vulnerable dry forest not a protected wetland because it is a well drained Sinkhole. Here water flows straight into the ground.
While there are a lot of wetland species in the Sinkhole, notably the majestic and here quite tall Eastern Cottonwood, they do not dominate the dry forest. The water loving Cottonwoods tend to cling to the brook that empties into the Sinkhole, while drier plant species cling to its highly elevated slopes.
Brook running into Sinkhole. Photo by Robert Hillier.
My friend Martin Munoz and I discovered the Sinkhole when we were looking for significant ecological features, being shocked into action by the threat of wetland Down Rating. After gliding over frozen Pin Oak lined vernal pools and seeing beautiful mushrooms and fungus growing out of ancient trees, we were startled to hear running water. Understanding that there was an unknown brook nearby we headed in the direction of the happy, babbling melody. We first encountered two small ravines, which joined and later crept into a deeper pit. At the bottom of a twenty metre sink, we saw the brook go underground, above a tall Eastern Cottonwood Tree. Some of its roots were exposed by the running water.
Eastern cottonwood tree over Sinkhole. Photo by Martin Munoz.
The magical scene Martin and I witnessed was identical to moving videos of the Eramosa Karsts sinkholes, made by the accomplished cave explorer, Michael Gordon. His work has greatly contributed to the need to protect Sinkholes, underground streams, caves and other features of Karst, (limestone and dolomite) formations to protect ground water.
(l) to (r): Sinkhole, Brook into Sinkhole, Martin Munoz and John Bacher, Photo by Robert Hillier.
In Hamilton south of the Niagara Escarpment Gordon’s opening up of caves once plugged by car parts leaking poisons helped to rescue what is now the Eramosa Karts Conservation Area from being paved over. One of the first stages of this process was to have the area designated by then Ministry of Natural Resources as an Earth Science Area of Natural and Scientific Interest. (ANSI)
One of the reasons for the establishment of Earth Science ANSI features is just so that people can understand and appreciate the wonders of geology. The experience that Martin and I had in Thundering Waters seeing a brook flow underground is one of these. People may read about elements of hydrology such as base flow from underground streams in high school text books, but the lessons are easily forgotten. They are seen vividly when streams flow down into the earth into an underground river.
While many people identify Karst formations with the rocky, Dolomite domed Niagara Escarpment, they also lie below extensive overburden of clay or sand soils. This describes the situation of the landscape of the defeated Dufferin County mega quarry, which is the best place in Canada to grow potatoes. Here Danny Beaton and I viewed the impact of the Karst fed drainage discharge that created conditions for the cold water stream in which we saw Brook Trout lead put of the river. At Thundering Waters under 20 meters of Welland Clay laid down by the vanished Lake Tonawanda is the porous dolomite which nourishes ground water. The collapse sink hole cut through the clay letting water replenish ground water through exposing the Karst rock.
Karst areas should be protected from development for a number of reasons. It is dangerous to build over them since these lands being vulnerable to erosion are prone to collapse. The planned expansion of Smithville was recently curtailed in part because of such features. The risk of collapse are increased near areas such as Thundering Waters by the soon to be retired power canal where excavation has brought ground water discharge. It is equally important that Kart area’s role continue to nourish underground aquifers that supply the ground water that keep streams alive in the summer time. This function will become even more important because of the drier summers expected in Niagara as a result of climate change.
While the Riverfront development is wrong in any shape or form, the worst aspect of it is the attempt to carve a road through the middle of a predominately old growth forest. The eastern edge of the development, if permitted at all, should be serviced separately through roads which do not cut up ancient woodlands.
While the term Thundering Waters based on the raging torrents of the Niagara River has put the its name into the hearts of others, the softer sounds of the brook flowing underground may appeal to our heads. It teaches that the water that nourishes our streams at their driest and most vulnerable moments, wells up from deep within the earth, from rocks that are normally invisible to our eyes.