Forested Wetlands

The Importance of our Forested Wetlands

“Wetlands support people and biodiversity and they are part of our common future under global climate change”
(from Cuiabá Declaration on Wetlands, approved at the 8th INTECOL Wetland Conference held 20-25 July, 2008, in Cuiabá, Brazil)

Let’s all raise a glass of clean water to our wetlands in the UNB Woodlot. This large expanse of forested wetlands represents a huge catchment area for rainwater and must be preserved.

Why do cities across North America spend tens of millions on preserving their wetlands? Because the costs of replacing the function of wetlands with stormwater and water treatment infrastructure are on the order of 10X more.

Nature does for free what cities need most: flood control, groundwater recharge, the storage and purification of water, habitats for birds and animals, recreation, and tourism. But wetlands comprise only 4% of New Brunswick’s land base and need to be protected.

Forested wetlands capture, store, and purify water. They provide habitat to a diverse group of plants and animals, including migratory birds. They represent the water we drink, the air we breathe, and the outdoor recreation spaces we enjoy. Urban wetlands act as a sponge and are integral to the watersheds of cities. Even in cities that get their drinking water from lakes or rivers, the integrity of watersheds surrounding the city help filter the urban runoff before it enters these bodies of water.

Stormwater pipes are no substitute for intact wetlands and forests within our city limits. The importance of wetlands to flood control cannot be understated. One acre of wetland can hold 1-1.5 million gallons of floodwater. In June 2008, the 500-year flood in Cedar Rapids, Iowa was a warning to the collision course between climate change and the loss of upstream wetlands to development. A severe rain event of 46 cm (18 inches) in 10 days saturated the soil to its carrying capacity and then the runoff swelled the banks of Cedar River. As wetlands are infilled and paved over, their rainfall capture ability is lost.

Wetlands are our insurance policy against climate change. The severity of runoff from severe rain events is affected by the size/layout of wetlands and the surrounding vegetation. The Toronto Ravine System is not only a recreational jewel but it cushioned the city from catastrophic damage in October 1954 when Hurricane Hazel dumped 12 cm (5 inches) of rain on the city in a day. Saint John received the same amount of rain in 2008 with Hurricane Hanna, resulting in severe flooding. The City of Saint John is now studying their drainage patterns in order to limit development in areas where flooding problems exist in areas below.

But New Brunswickers can learn from these floods. The UNB Woodlot is a 3800-acre forested wetland situated at the top of Fredericton equal to the size of the southside Fredericton and Lincoln in the valley below. Just like an egg cracked over a person's head, rain captured by the UNB Woodlot supplies the headwaters and tributaries of Corbett Brook, Phyllis Creek, Garden Creek, and Baker Brook watersheds, and smaller watercourses that flow through Fredericton and towards New Maryland. Not only do these forested wetlands contribute to our aquifer - the sole drinking water supply for the City of Fredericton - but they act as a giant sponge during severe rain events and slowly release the water to surrounding forests and aquifers that supply our drinking wells. These urban wetlands are our insurance policy against climate change.

The economic benefits of these forested wetlands are large, but fortunately for us taxpayers, they are free. The surrounding forest cover prevents excess rain from overwhelming these watercourses; the tree buffer is crucial to the water capture capacity and connectivity of these wetlands – and now they are under threat of development. Benefits such as rainfall capture and run-off control would be seriously compromised if the present development strategy is allowed to fragment these wetlands. If this water absorbing capacity of wetlands is fragmented or lost altogether by development, the taxpayers of Fredericton would be saddled with the cost to build replacement infrastructure for storm water management. Unfortunately storm water pipes and retention ponds are an inferior solution so we would also be saddled with flooding costs.

In this electronic age, the natural world is important for the healthy emotional and intellectual development of our children. Urban forests are magnets for exploration, adventure, hiking, mountain biking, and learning about nature. Wetlands are natural teaching classrooms for our children. Thousands of Grade 4 children have visited the Ducks Unlimited Corbett Brook Marsh in the UNB Woodlot to learn about the diversity of plants and animals in these unique habitats. Wetlands also serve as outdoor labs and research for students in colleges and universities.

The future climate scenarios for the Fredericton/New Brunswick region are sobering. Conservative computer models by Environment Canada predict major changes this century: severe rain events are expected to increase in number and severity with climate change; a 30% increase in winter precipitation; more winter runoff (2X); significant increase in freeze-thaw cycles (in winter); lower summer/fall runoff (1/2); 3.1 to 5.9 *C increase in mean winter temperature; and 2.4 to 5.1 *C increase in mean spring temperature. The combination of severe rain events with more winter melt will increase our risk of floods. Rain-saturated soil provided the perfect conditions for the great spring flood of 1973 in New Brunswick. Also, significant increases in rainfall and wind speeds of hurricanes will both be fueled by warmer water temperatures in the Atlantic. Notable hurricanes that caused flooding in New Brunswick include Carol (1953), Edna (1954), Gladys (1968), Belle (1976), Bertha (1996), and most recently Hanna (2008). And as this article is written, Hurricane Kyle was forecast to deliver up to 10 cm of rain over New Brunswick - a day after receiving already 5 cm of rain - but fortunately we did not take a direct hit.

Drainage planning, watershed-based source protection planning, and comprehensive land use planning will protect our drinking water and homes for future generations. And don’t forget the beavers. Glaciers and geomorphology are the main creators of wetlands, but beavers have a major role in forest waterways becoming ponds and wetlands. Manage the beavers using humane anti-flooding devices, and, in turn, they will manage the wetlands. Proper road design using arched or gull-winged culverts eliminate much of this work altogether since the beavers can't block them.

Urban forested wetlands are well worth preserving. Our governments have an obligation not to pay for inferior solutions when nature provides a priceless solution for free.