Wetlands come in many different forms — from marshes and swamps to shallow ponds and estuaries. The shallow-water shorelines of many lakes, rivers and oceans are wetlands. Any land depression where water accumulates in or just above the soil for much of the year is a wetland. With the exception of mountain tops, deserts and the extreme polar regions, it is possible to say that "wetlands are everywhere." Yet, even an oasis in a desert will have wetland characteristics.

But what exactly is a wetland? As Zoltai observed in Wetlands of Canada (p. 9), "A universally accepted definition of wetlands has not emerged because of the diversity of users and the regional variations of wetlands." That desert oasis and Burns Bog may both be called wetlands, but we need to understand which characteristics classify them both as such. The definitions with which we must live, of which there are more than fifty around the world (Dugan, p. 12), are somewhere in the middle. Here are some examples:

"A wetland is simply any area of land that is covered with water for a part of the day or a part of the year. There are two classes of wetlands: freshwater and saltwater." (From Wetlands, a Canadian Wildlife Service pamphlet.)

"They [wetlands] are neither firm `lands' in the conventional sense nor bodies of open water; hence they occupy a transitional position between land and water. The ecosystems that develop on such lands are dominated by the persistent presence of excess water. Wetland is de fined as `land that has the water table at, near, or above the land surface or which is saturated for a long enough period to promote wetland or aquatic processes as indicated by hydric soils, hydrophytic vegetation, and various kinds of biological activity that are adapted to the wet environment'." (Tarnocai in Wetlands of Canada, p. 3.)

"Wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres." (International definition adopted at the 1971 Ramsar Convention on Wetlands.)

We can think of wetlands as places where the biological world can re-create and re-invent itself. Life on earth may have begun in the ocean, but it really began to diversify and become interesting once it extended to the amphibious realm, the wetland realm. Wetlands are places that are rich in possibilities, dense with different habitat niches, and sufficiently complex that they offer a model of the kind of diversity that scientists know is needed to sustain stability and genetic health in the global ecosystem. Looking at it this way, you could say that wetlands are the earth's way of providing places where life as we know it could have evolved and will continue to flourish.

What are the Different Types of Wetlands?

The distinctions between and among wetlands are based on such characteristics as water levels, whether floods occur, the acidity of the water, the type of soil, the types of plants, and the amount of woody plant material. It is important to remember that all wetlands are worth preserving. Some, however, will be assessed as more valuable than others because they are a rare type of wetland, provide a vital link in a "greenways" scheme, or because they contain rare or endangered species.

There are many ways to approach the classification of wetlands. The broadest categories of wetland are called classes. There are two classes of wetland: freshwater and saltwater.

Freshwater: Shallow ponds and potholes, marshes, peatbogs, swamps, fens, wet meadows, swamp forests, floodplains, and most shorelines (the exception being those shorelines that are extremely steep).

Saltwater: tidal flats, saltwater marshes, eelgrass beds, estuaries, and deltas.

Another method of classifying wetlands is based on five types of wetland systems (from Niering, p. 21):

The total number of wetland types is truly bewildering — see the list at the end of the book for a sample of wetland descriptive terminology. There is enormous overlap in the terms used and because of that the short lists given above are perhaps a better guide to the wetlandscape.

Why are Wetlands Important?

Wetlands offer an extraordinary variety and number of habitats for creatures seeking a home. Wetlands are important as a home for their own inhabitants as well as for the inhabitants of nearby ecosystems of other types. A wetland in one locale is important for migrating birds that are thousands of miles away.

An understanding of food chains, animal habitat provided by plants, and the provision of water in dry seasons will come easily to anyone familiar with basic ecology. Each of these is a key aspect of what is valuable about wetlands. Differences in point of view regarding the value of wetlands often stem from differences in understandings about the basics of ecosystems, and their importance.

Many writers have called wetlands the kidneys of the earth because they filter and clean the water that flows through them. But they are also the bladders of the earth by virtue of their water storage ability. For their role in transforming nutrients, wetlands are also the earth's digestive tract, and for their ability to filter toxins, they are the liver as well.

One answer to the question of why wetlands are important is the same as the answer to the question: What good is a kidney? By filtering the body's fluids the kidneys help support the biological functions around them. Wetlands, through their role in providing habitat and supporting biodiversity, do just the same — they support life, including filtering the fluids that pass through them.

Benefits of wetlands

• Water purification
• Flood protection
• Groundwater recharge and stream flow maintenance
• Shoreline stabilization
• Fish and wildlife habitat
• Rich source of biodiversity

The value of our remaining wetlands has increased dramatically over the past few decades because so many wetlands have been destroyed. The days are gone when one could assume that there would always be another wetland habitat to take the place of one that was filled or drained. Seventy per cent of the wetlands near many Canadian cities and towns have been destroyed, mainly in conversions to agricultural uses. (See Wetlands in Canada: A Valuable Resource.) At some time in the past there may have been "other places to go" for wetland creatures, but that option has been lost as a result of one hundred years of wetland destruction.

The richness of wetland habitat is exploited when wetlands are converted to agricultural uses. Many centuries worth of organic material has built up, and it can then become productive farm land, but only at the expense of the food chains (or food webs) that once functioned at that site. That this richness is so prized by farmers is an indication of just how important these wetlands are in the global ecosystem.

Every wetland provides many different types of habitat; part of the richness of wetlands is to be found in the fact that they have many different habitat niches. Each niche is like a universe unto itself that is preyed upon and utilized by creatures in the adjacent universes. The sheer number of niches, and their variety, is a function of the transitional nature of wetlands; they are neither water nor land, but every imaginable combination of the two crammed into a finite area. Everything that wetlands cannot do for humans directly is exactly what they can do for other lifeforms — wetlands provide shelter and food; they are the factories and nurseries of our landscape.

Wetlands and Flood Control

One of the greatest virtues of wetlands is their ability to control floods by absorbing water. Approximately 100,000 cubic kilometres of water falls on the earth every year as precipitation, and about 25 per cent of that flows over the land surface as run-off. Perhaps the best way to imagine how wetlands work to slow down this cascade and mitigate the damaging effects of floods is to picture 25,000 cubic kilometres of water falling on a paved surface — which, for the purposes of this discussion, is the opposite of a wetland.

In the United States, some 520,000 square kilometres of land — an area approximately the size of France — have severe flooding problems. In 1995 and 1996 there was severe flooding in the Pacific Northwest, which many suspect was partially the result of wetland loss and destruction. If thousands of hectares of wetlands had not been destroyed, these catastrophes might not have occurred, or at least would have been minimized.

How do wetlands perform these protective functions? Even though a wetland is already wet it will always have room for more water. Wetlands give incoming waters "cause for pause," and they do it without damage to themselves. Patterns of water-flow concern humans greatly during storms and droughts. During storms, our wetlands help protect us from floods by absorbing and holding water before releasing it. In dry periods, a wetland is a valuable source of water. This is the sponge-like function of a wetland — gradually releasing valued water while absorbing more if it comes along.

Think of wetlands as devices for seizing water, using it, cleaning it, and then gradually letting it go on to serve other uses.

Getting the message to your town council about the sponge-like function of wetlands can be an important step in getting town/district officials on-side for future wetlands debates. Describing the flood-control function of wetlands to elected officials will be rewarding if it helps them understand why wetlands need special protection.

Filtration — How Wetlands Clean Water

Regardless of our point of view, we must accept that wetlands are the great purifiers of the waters of the earth. Wetlands are a natural answer to the question of water quality. "Wetlands, once regarded as a source of disease, can actually help maintain water quality, promote the rapid growth of plants, absorb toxic metals and chemicals, clean up polluted water, and even act as natural sewage treatment plants." (Maltby p. 63.)

This becomes clear when we consider sediments, such as the fine sand found in turbid, fast-moving rivers. This sand is in the water until the water slows down — when it slows down the sediments drop and you get either a wetland or a delta that will soon be a wetland.

The filtration function of wetlands is not limited to sediments and toxic compounds. For example, it is our wetlands that have saved us from an environmental catastrophe caused by all the excess nitrogen in fertilizers that have been dumped on the earth since around 1920. Not only is some of the excess nitrogen converted into wetland plant life but wetlands contain bacteria that can reduce the oxygen in nitrates, and convert the nitrogen back into the atmosphere as a gas. Without this ability, which is called denitriphication, our environment would have long ago choked on an overdose of nitrates. For a summary of wetland filtration see Laura Jamieson's article in BCWETNET NEWS #4.

The Links Between Mapping and Definitions

Wetland mapping is dependent on having clear wetland definitions because boundaries can only be established in relation to an agreed-upon set of wetland characteristics. Figuring out where a wetland ends and the next ecosystem begins is the key to visualizing where a wetland exists on a map, as well as where it exists on the earth. The process of defining wetlands, either on paper or in the field, is called mapping. (In the United States it's called delineation.)

Wetland protection will be incomplete unless there are laws about how close to the edge of a wetland development activities can occur. To function as healthy ecosystems wetlands need buffer zones around them. How far from the edge of a wetland do you have to be before your activities no longer affect the wetland ecology? Wetland animals use the adjacent ecosystems, so from the point of view of plants and animals, those non-wet places are an extension of the wetland. Thus, the answer to the question: What is a wetland? is directly linked to the answer to the question: Where does the wetland begin and end?

Mapping and defining wetlands are interrelated. When the definitions of wetlands are questioned, people often want to change the mapping/delineation of wetlands so that fewer wetland areas meet the definition. Conversely, if our definitions are more inclusive, then more land can be classified as wetlands — to the benefit of entire communities.

Why are Wetlands Misunderstood?

Only recently have people perceived and comprehended the value of the indirect benefits of wetlands. While the benefits are clear for their biological inhabitants, for humans it takes an understanding, for instance, that without wetlands BC's salmon population would disappear. Therefore, unless we have some knowledge of these indirect benefits, we won't know they even exist.

The gap between direct benefits and indirect benefits can be filled only by education and understanding. Two initiatives would go a long way toward filling this gap — a comprehensive wetlands education syllabus for the public school system and a compulsory wetlands module for all students of town and regional planning. Other important tools are strong wetland protection laws and continued media coverage of wetland issues.

Many commentators on wetlands, including Bill Nye on the Science Guy show on PBS, have wondered if our misunderstanding of wetlands can be traced to the tensions that exist between humans and insects. Maybe so, but in any event we need to counter this attitude by convincing people that wetlands are important. Confronted by an unsympathetic elected official, you could try saying, "I am bothered by mosquitoes and blackflies as much as the next person, but I think of these insects as food for dragonflies and birds, and I imagine that had we not destroyed so much of Canada's wetland habitat there would be enough birds to clear the air." The point being that the solution to excess numbers of insects is not the draining of more wetlands, but the restoration of our lost wetland habitat.

Wetland Formation

All that is needed to have a wetland is a place where standing or slow-moving water can accumulate. Why is the earth's water where it is? There are two reasons; one topographical, the other climatological.

Our earth is full of pockets that are like nests for water, and those pockets often become wetlands. Many places that are now lakes and rivers will gradually be filled in with sediment and become wetlands. A flat earth (i.e. an earth with no hills or mountains) would probably be one big wetland.

Human activity continues to play a major role in the formation of wetlands. Excavations, logging, and flooding due to dam building, sewage lagoon construction and dyking, are all capable of creating wetlands. Maltby (p. 29) gives the example of logging in Great Britain which triggered soil changes that led to changes in vegetation and hydrology and set up the conditions for bog formation. The erosion resulting from logging created wetlands by modifying the height of the water table.

Wetland conditions do exist in places where there may be little standing water. On BC's Pacific coast, wetland conditions are created on mountain slopes as a result of precipitation. Hydric soils and hydrophitic vegetation are found on mountain slopes that rarely have a chance to dry out. (See Wetlands of Canada, pp. 307 to 345.)

In short, wetlands are the natural outcome of the earth's geological formation, its meteorological cycles, and its climate. In true Darwinian style, it could be no other way unless, that is, the "artificial selection" of draining and filling is allowed to overtake the "natural selection" of leaving our wetlands undisturbed but evolving.

Wetland Processes

Descriptions of wetland processes are somewhat complicated by the sheer variety of wetland types — each wetland type has processes that differ from other types in some basic way.

In battles over wetland protection, therefore, we must be clear about exactly what it is that we are protecting. It may be that one's favourite wetland is in fact an algae-filled, oxygen-starved, nutrient-poor pond that may eventually evolve into a meadow. It is nevertheless an important habitat, with vital roles to play in the ecosystem.

In many ways, the form of a wetland, and its processes, are directly related to its hydroperiod. This term sums up all the different seasonal or daily variations in water input that form a wetland. In tidal wetlands this inundation may be twice daily, once monthly, or permanently flooded, as in subtidal eelgrass beds. In non-tidal wetlands, the hydroperiod ranges from seasonally predictable to randomly timed flooding. The form, organization, and hence the type of wetland, all rely on these patterns of water input.

Any given wetland may have characteristics of more than one wetland type. As conditions change, especially water input, the bio-profile of the wetland may change. This is important, not only because it is ecologically fascinating, but in any study of the status of a given wetland it is best to think of it as being multifaceted. For instance, one would not want to file a court challenge in winter to protect a wet meadow and have it come to court after a drought in late summer when it had dried out and had as many grassland indicators as wetland indicators.

So, the organization of a wetland — its metabolic processes, as measured through various functions that are analogous to digestion, blood circulation, and waste removal — will be a function of its topographic setting, its substrate (the underlying geological structures), and the particular rhythm with which water enters and leaves the wetland — its hydroperiod.

Wetland Characteristics

The attempts to describe the characteristics of wetlands are at the core of why wetlands often remain disputed territories. The disputes, to date more frequent in the US than in Canada, often rage around the distinctions between what is a wetland and what is not. The status of a wetland may depend entirely on which characteristics one accepts as legitimate.

Here are the general characteristics of wetlands:

• Water. Wetlands are characterized by the presence of either surface water, sub-surface water, or both. The water may be present all of the time or only some of the time.
• Vegetation. Wetlands support plants that are indicative of wet sites. This sounds circular, and it is, but it is worth noting that the presence of certain plants is proof that a place is in fact a wetland. These plants, called hydrophytes or hydrophitic plants, are only found in wetlands.
• Soil. Wetland soil is called hydric soil. Hydric soils have physical and chemical properties that are characteristic of waterlogged conditions that lead to an almost complete lack of oxygen.

It might be possible to add wetland animals to this list, but animals are too mobile to be properly included in any classification scheme.

Wetland Hydrology and Soil

Hydrology is what wetlands are all about — water in contact with land. Wetland hydrology is the study of, and the description of, the ways water moves in and out of a wetland. The balance between the inflows and outflows of wetland water is called the water budget. The water budget will affect everything about a wetland, from its general type to its nutrient make-up, from its species profile to its value as a tourist destination.

Water enters a wetland via tidal flows, periodic flooding (from either surface or groundwater sources) or precipitation. Water exits a wetland by gravity (which forces it downstream), through evaporation, or through transpiration from plants. One or another of these processes, or a combination of them, will be dominant in any particular wetland — which will give the wetland what is called its hydrological signature.

These definitions are important to know when you are claiming that a given site is a wetland. But note that assessing soil as hydric (or not) will often require either sophisticated instruments or the advice of a wetland scientist, or both.

Plants, Animals, and Habitat

A visit to the Reifel Bird Sanctuary in Ladner (25 minutes south of Vancouver by car) shows that wetlands are popular tourist destinations because they are teeming with wildlife.

Wetlands are wonderfully well equipped to provide wildlife with a place to live. Given a certain richness and diversity of nutrients in a wetland, there will eventually appear a richness and diversity of wildlife. Micro-organisms love wetlands, as do those who eat the micro-organisms, and so on up the food chain to the duck hunters and crayfish farmers. Wetlands are usually downstream from other ecosystems and, as a result, they are net importers of the nutrients, biomass, and energy that gravity washes downhill. When all this material gets to the wetland, it slows down or even stops moving completely, and becomes part of the wetland's metabolism.

Wetlands are among the most productive of all ecosystems on earth. (However, it is important to note that while this is true of most wetlands, it is not the case with every wetland type.) This massive productivity is measured not only by the amount of life the wetland can create but also by the amount it can sustain. One result of this huge productivity is bio logical diversity. It is now an irrefutable truth of biological science that diversity is crucial to the well-being of life on this planet, and that wetlands are a magnificent source of biodiversity.

Diversity provides stability because any large-scale losses or gains in species or populations are offset by other species or other populations. Biodiversity is nature's best defence against the negative effects of species monoculture and the decline in genetic health that attends excess inbreeding. Wetlands are the opposite of monoculture — the problems that continually beset the monocultures of agribusiness are never problems for wetlands. You'll rarely see too many pests, dustbowl soil, or rampaging floodwaters in a natural wetland. That's because wetlands have what monoculture, by definition, lacks — complexity, diversity, and, as a result, the ability to deal with environmental change.

This diversity in wetlands applies equally to animal life, plant life, and micro-organisms. Not only are wetland habitats diverse, they are often the most secure of all animal habitats, and it is for this reason that wetlands are described as a "refuge" — a place where non-wetland predators can't get. The relations between wetland creatures and their habitat can sometimes be paradoxical. For example, some wetland predators are responsible for sustaining the populations of their prey. Maltby (p. 78) gives the example of a species of fish in the Amazon that died out when its main enemies, two species of crocodiles, were removed — apparently the crocodiles' excreta were a key element in the food chain that supported the fish.

Shoreline Wetlands Riparian Zones

Riparian zones are shorelines. They are found at the edges of most bodies of water and form the wetland component of oceans, rivers, harbours, and lakes. Riparian zones include riparian forested wetlands — these are all those treed shorelines that are occasionally flooded but remain dry during the growing season. (Mitsch and Gosselink, p. 41.)

Riparian zones are extremely important habitat, especially here in BC because of the supportive role they play in maintaining the salmon population. Riparian zones are a transi tion area where the life of the upland slope (the watershed above the wetland) meets the wetland.

Riparian zones are wetland areas with a difference. The difference is that they are usually in direct contact with, and are therefore directly influenced by, a large body of water such as a river or a lake. A riparian zone along a river is essentially a linear wetland — if the river is 200 kilometres long, then the riparian zone will cover most of the 400 kilometres of shoreline. Sometimes the two opposing shorelines are very close, other times they are so far apart as to be part of two separate habitats.

Marine riparian zones have their own names, such as "tidal flat," "the shore of the estuary," or "the edge of the salt marsh." These riparian zones will all be, at most points in their geography, shoreline wetlands.

The importance of riparian areas is in part due to their abundance. For example, riparian forested wetlands (and their associated deepwater swamps) are the most "extensive class of wetlands in the US, covering 22.3 million hectares." (Mitsch and Gosselink, p. 40.)

Upland Slopes — The Watershed Above the Wetland

Wetlands are as ecologically connected to the land that surrounds them as a child in the womb is to its mother. A riparian zone at the shoreline is not unlike the membrane through which metabolic exchanges take place between mother and child. Two important questions arise from this: Where does the wetland end? How much of the upland slope has to be protected in order to protect the wetland?

A wetland ends at the point where the three basic characteristics of wetlands are no longer present. (See pages 14-15 for basic characteristics.)

In British Columbia, upland slopes, especially in suburban areas, are being destroyed at a breakneck pace. The nutrients that once flowed down hillsides are now locked underneath pavement, homes, and lawns. The natural cycle of the watershed, which gradually transfers both water and nutrients to the wetlands below, is disrupted. This leads to nutri ent starvation and droughts, because pavement prevents water from seeping into the earth. Culverts and other surface-water control systems also divert water away from its natural destination — our wetlands.

Upland slopes need to be protected if the wetlands below them are going to remain healthy and alive. But these higher zones are most often selected for new development. How do we get around this? The answer lies in environmentally sensitive development. In other words, development that does not have as its primary goal the placement of the maximum number of lots on a site, or the largest houses on the smallest lots. The retention of forested greenways through a site will preserve some of the functions of the watershed.

Municipal councils and planning departments are sometimes unaware that there are sensible methods of development that do not destroy the local ecology. This is true not only for upland slopes but for wetlands as well. The case study, examined in BCWETNET NEWS #1, of a Gulf Island subdivision in a wetland shows that development and housing can co-exist. Because the lots in this development on Bowen Island were in a preserved natural environment, they were more valuable than they would have otherwise been. The developer lost no money even though the wetland was preserved in its entirety, and even enlarged from its original state.

Wetland Succession — How Wetlands Change Over Time

Wetlands are not static entities. They are alive — as alive as any organism — and like an organism, they exhibit a day-to-day, moment-to-moment transfer of energy from one realm to another, one place to another, and as with any metabolizing organism, they also change naturally over time. This evolution is called succession, which is a polite term for aging. A maturing deciduous forest evolving into a coniferous one is said to be undergoing forest succession. A maturing wetland, however, can evolve in any number of ways.

In a sense, a wetland's greatest natural enemy is itself. The ongoing creation of biomass, which accumulates as detritus, combined with the useful ability to absorb inflowing sedi ments, leaves many shallow wetlands doomed to evolve — first into meadows and eventually into forest floors. As a wetland shrinks, more and more non-wetland plant species take hold at the receding shoreline. And this in itself can accelerate the succession process. But because the water from the original wetland has to go somewhere, it is probable that a new wetland area will form nearby.

Succession occurs in coastal waters as well. River sediments alone can build up and extend a shoreline, leaving one-time estuaries far inland. Dugan (p. 18) gives the example of the ancient port city of Palenburg on the north coast of Sumatra, which was visited by Marco Polo in 1292 and is today 50 kilometres inland.

Human activity can play a significant role in succession: "Altered drainage has the most widespread effects. A lowering of the water table allows shore pine, western hemlock, and paper birch to expand at the expense of sphagnum and other bog species in basin and domed bogs." (Wetlands of Canada, p. 342.) Peat mining brings about the possibility of flooding, and the succession from bog to marsh.

Should we interfere in the process of wetland succession? There are many reasons for doing so, given the amount of wetland destruction that has taken place. Some intervention will be required just in order to maintain our current inventory of wetlands. Preserving habitat is always worthwhile but attempts to recreate wetlands are tricky and fraught with peril. (See "Restoration" below.) Meanwhile, it is important to be clear about the distinction between slow, gradual succession and the destructive rapidity of development. Development and wetlands can co-exist, but care must be taken with the form and pace of development near ecologically sensitive areas such as wetlands.

Ponds evolving into marshes, marshes into fens, and fens into bogs, are all part of the ecological process called succession. They are all natural, gradual, and benign facets of the life of our wetlands.

Wetland Restoration and Creation

One of the most surprising things about wetlands is that an artificially created wetland can be just about as good as a natural one. Wetland restoration involves making a healthy wetland where one previously existed. This may involve nothing more than restoring the natural hydrological conditions and letting nature take its course. Wetland creation involves making a wetland where none has been in recent memory.

There are some questions to be asked about the soundness of creating or restoring a wetland. The answer is relatively easy for restoration — it should always be desirable to restore a wetland to a place where there once was one. Creating a wetland is more complicated. What habitat is being lost to create the wetland? Which of these habitats is more important, especially given the costs of wetland creation? Government agencies with "no net loss" policies (i.e., that any wetland loss will be mitigated by creation of new wetlands of equal size) have to deal with these complexities. Often community groups, those with a desire to experience the joys of having a local wetland, will be the initiators of restoration/creation projects.

The reasons for restoration and creation are the same as the functions of wetlands: habitat creation, flood control, water quality improvement, recreation, nature study, and shoreline erosion control. In addition, created wetlands are commonly made for wastewater treatment. (See Martin Keeley's article on the Dawson Creek lagoons in BCWETNET NEWS #5.)

Kentula's book Wetlands: An Approach to Improving Decision Making in Wetland Creation and Restoration explains just how complicated the process can get. When the project is on public land and requires taxpayers' money, the need for expert advice is ecologically and politically compulsory. What one wants to achieve during the proposal/planning stage of a restoration/creation project is "a framework for the development of ecologically defensible management strategies for restoration and creation that are tailored to local and regional needs." (Kentula, p. 3.)

So, unless you just want to experiment with a patch of land on your own back forty, the restoration and creation of wetlands will need expert advice and consulting. A critical review of the proposal will be a key element in the success of the project. Costs of maintaining the site must be assessed, and the problem of long-term monitoring of the new wetland's health must be addressed early on. Will this be done by volunteers? Who will train them? Kentula's book, in addition to having an extensive bibliography related to this topic, has an entire chapter on the use of volunteer monitors.

If you're in the lower mainland and wish to see some created wetlands, visit the pond site at Jericho Park on the west side of Vancouver, or Trout Lake on the east side. The Fraser River Foreshore Park, Ladner Lagoon, Iona Island Park, and Sea Island Park are also well worth a visit. (These sites are listed in The Discoverer's Guide to the Fraser River Delta by Don Watmough.)