Why are Headwaters Important Before we start just

Why are Headwaters Important?

Before we start, just a reminder from What are Headwaters? … In general, headwater streams are 1 st, 2 nd , and 3 rd order streams and their catchments, and … Other aspects of headwaters include: • Vernal pools; • Off-line Ponds; • Parts of the Groundwater System; and, • Wetlands.

As also stated in What are Headwaters? -Headwaters are the foundation of our watersheds. ___________ Let’s explore this by looking at: 1. Stream Length; 2. Surface Area; 3. Water Quantity; 4. Water Quality; and, 5. Biodiversity.

1. Stream Length Maybe we don’t think a lot about headwaters because they aren’t on the front page, but … headwater streams form the majority of the total length of all streams in any watershed.

1. Stream Length For example, the length of just the 1 st and 2 nd order streams of the Rouge River account for 67% of its total stream length.

1. Stream Length

2. Surface Area As might be expected from the information on stream length, headwater drainage areas, called catchments, drain the majority of a watershed’s area.

2. Surface Area Although hard to see in this photo of the northern Credit, where the headwater catchments are shown in yellow, just the 1 st and 2 nd order catchments make up 67% of the watershed. This jumps to 76% for the Kawartha, and over 90% for the Rouge.

3. Water Quantity Headwaters and their catchment areas influence water quantity in two key and complementary ways: i. They provide the bulk of the flow to our watercourses; and, ii They regulate that flow, to both surface and groundwater, through natural cover, soil type, and geology.

3. Water Quantity This ability to regulate flow from areas in natural heritage, such as forests and wetlands, impacts: i. local soil moisture & plant types; ii. infiltration to groundwater; and, iii. the speed and volume of run-off, thereby influencing downstream erosion and flooding.

4. Water Quality Headwaters have exciting journeys. They babble through forests, meadows, and valley corridors; weave through wetlands; and seep in and out of streambanks and groundwater.

4. Water Quality Along the way, headwaters pick up, blend, and deposit significant portions of a stream’s nutrients, organic matter, and sediment, thus defining water quality downstream.

5. Biodiversity All of the features above enable headwaters to nurture the largest portion of a watershed’s biodiversity, providing a variety of key habitats for the breeding, feeding, and sheltering of numerous species.

5. Biodiversity i. About 33% of all Canadian species require wetlands at some point in their lives; ii. Most of the larger species downstream depend on the smaller species upstream; and, iii. Terrestrial insects are as important a part of this food chain as are aquatic insects.

In summary, headwaters are extensive, and they fill significant ecological roles for our watersheds, their biodiversity, and us. While humans need to live somewhere and harvest resources, we need to act as responsible stewards in our headwater areas.

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