What are Headwaters?

When most people think of Ontario’s water, they may think about “big water”, such as The Great Lakes and the St Lawrence River Lake Nipigon Lake Simcoe or some of our massive northern rivers, such as the Moose, Albany, Attawapiskat, Winisk, or Severn

All of Ontario’s watersheds, however … are highly dependent on their headwaters, in numerous ways.

So, what exactly are headwaters? Headwaters are the foundation of our watersheds, and include: 1.Small streams & their drainage areas 2.Vernal Pools 3.Off-line Ponds 4.Parts of the groundwater system & 5.Wetlands

Let’s examine each of these.

1. Small streams and their drainage areas In general, headwater streams are 1 st, 2 nd, and 3 rd order streams, as per the drawing.

i. a 1 st order stream is one with no tributaries; Keys aspects of headwaters include: ii a 1 st order stream can occur anywhere and flow into the ocean, a lake, a wetland, or any part of a river; 1. Small streams and their drainage areas

iii. a 2 nd order stream starts where two 1 st order streams meet; Keys aspects of headwaters include: stream order is not affected when a smaller order stream joins a larger stream; iv. As per the yellow circle, 1. Small streams and their drainage areas

v.Headwaters can be either EPHEMERAL – where flow is based on precipitation or meltwater, as shown in this photo from Short Hills Provincial Park, or Keys aspects of headwaters include: INTERMITTENT – where flow occurs when the water table rises; 1. Small streams and their drainage areas

Keys aspects of headwaters include: it is in fact just a 12 th order stream! and… vi. Higher stream orders drain increasingly large areas. For example, while you might think that the Amazon, the world’s largest river, is a 32 nd or 55 th order stream, 1. Small streams and their drainage areas

vii. Regardless of the size of the river, headwater streams and their drainage areas make up significantly proportions of a watershed’s stream length, surface area, water quantity, water quality, and biodiversity*. 1. Small streams and their drainage areas * See Why are Headwaters Important?

2. Vernal Pools Vernal pools are temporary features that form mostly as a result of precipitation, providing important spring habitat for amphibians and waterfowl. Vernal Polls both evaporate and drain into local groundwater.

3. Off-line Ponds Off-line ponds are normally spring-fed and do not have surface connections to other local waters. Note: An off-line pond differs from an on-line pond in that an on-line pond occurs along a stream.

Portions of the groundwater system that are part of our headwaters include: Groundwater re-charge areas; Shallow aquifers and wells; and, Areas of groundwater discharge or up-welling. 4. Groundwater

Ontario has a high degree of interaction between ground and surface waters, due to both the sand and gravel in the Oak Ridges Moraine and the fractured rock in the Niagara Escarpment, as per this photo. 4. Groundwater

5. Wetlands: Marshes are areas with lots of open water and plants such as water lilies and cattails - such as at the olde swimming hole at Terra Cotta; There are four types of wetlands, including: i. Marshes -

ii. Swamps - Swamps are wet areas dominated by trees and shrubs, such as this one at the Britton Regional Forest, Halton; 5. Wetlands: There are four types of wetlands, including:

iii. Fens - Fens are ground-fed areas that are usually high in levels of dissolved minerals and are dominated by sedges, grasses, and reeds, such as this one in the Fletcher Creek Ecological Preserve; and, 5. Wetlands: There are four types of wetlands, including:

iv. Bogs - Bogs are peat-filled areas with water that is acidic and low in nutrients, with little plant diversity, such as this northern Ontario boreal bog. 5. Wetlands: There are four types of wetlands, including:

. Now that we’ve seen what headwaters are, such as this 3 rd order reach of the Credit River flowing through a provincially significant wetland near Alton, Ontario … please see Why are Headwaters Important?

Thanks for watching. ontarioheadwaters.ca