Water Column: Slow flow, part III (conclusion)

Compared to most indicators for 2020, the Water Year is closing relatively smoothly.

Compared to most indicators for 2020, the Water Year is closing relatively smoothly: We had a decent snowpack and it didn’t melt and run off super early.

That said, Part I of this series just last month described the keen focus of many professionals in the farming and salmon habitat communities on Dungeness River flow gages as September approached.

The flow, dependent on snowmelt through the summer, had already dropped low enough in August to require irrigators to decrease their diversions from the Dungeness.

Flow continued to drop below 100 cfs (cubic feet per second, about the volume of a basketball, measured upstream of the Dungeness Fish Hatchery) — with no rain in sight.

When I wrote Part II in early September, the river was looking dangerously low for salmon trying to pass through and spawn.

Two rain showers in the middle of the month helped for several days but early last week flow dropped way down again, below 90 cfs. Water in the channel at that point was mostly baseflow emerging from the ground.

Our natural reservoir of snowpack in the mountains was melted out.

But we all know what happened next. The final week of Water Year 2020, which ends today, began with a deluge. The river shot from 89 cfs to around 300 cfs in 12 hours last Wednesday and hovered there for two days before shooting again to 870 cfs.

I guess our rain dance was successful!

Tight budget

Last time I said you can’t tighten the belt on a water budget and that our annual salary of snow and rain has declined — to the poverty level — with cuts, not raises, expected in the future.

I asked, “What can we do about it?”

1. Get more efficient

For three decades, water managers and other stakeholders in the world of farms, salmon, and water supplies have been working on the late-summer low flow issue – the gap between what fish need and what the river provides.

Irrigation managers and supportive state and federal granting agencies have completed projects that conserve water to benefit stream flow, such as piping more than 100 miles of leaky irrigation ditches — in comparison, City of Sequim has 72 miles of drinking water pipe — and converting to more efficient irrigation methods.

According to Joe Holtrop, Executive Director of the Clallam Conservation District (which manages the vast majority of grant projects for the irrigators), “We estimate total water savings to be over 31 cfs” since 2000.

Given a low flow below 90 cfs when the river enters the lowlands, that’s extremely significant.

2. Fine-tune

Another way to get more efficient is to make the most of what you’ve got. Like irrigators, biologists have worked tirelessly to restore habitat with the goal of recovering healthy populations of the nine different “salmonid” species in the Dungeness.

Dozens of projects in the past three decades have made streams more functional to migrating salmon than when their stream banks were rip-rapped, diked or denuded of trees and logs.

3. Make new water

OK, it’s more of a shell game, but because of the direct connection between groundwater and surface water, raising the water table can result in more water in the stream channel.

So-called managed aquifer recharge projects, often taking advantage of old leaky irrigation ditches, aim to supplement the water table in specific places and times such that it will benefit flow in down-gradient streams when even 1 cfs would help in late summer.

This type of project is used to mitigate the impact of more and more wells going in, drawing the water table down.

Another example is the project underway moving the levee on the east bank of the lower Dungeness River further east, re-opening the original floodplain and side channels used by salmon at various life stages.

Clallam County’s Cathy Lear describes restoring the hydrology like this: “We expect flood waters to spread out and percolate more slowly into the floodplain, stabilizing the water table.”

Aquifer recharge, the natural way.

4. Store it

As reservoirs of ice and snow in the mountains shrink over time, reservoirs to store winter rain and runoff will become essential.

A current proposal to build one along south River Road is creative in that stored water will be available for irrigation in late summer when snowmelt in the Dungeness may not be, and keeping up to 25 cfs in-stream.

5. Everyone can conserve

Finally, since virtually all eastern Clallam County households are served by wells tapping our aquifers, everyone using water has the ability to positively — or negatively — affect the water table and therefore streamflow in late summer: we can all avoid over-use and not water a lawn, and we can all make sure rainwater recharges the aquifer (captured and infiltrated in a rain garden or drywell, for example).

No guarantees

A good rainstorm in August or September can make all the difference for salmon and commercial irrigators dependent on the Dungeness River. Thanks to our deluge last week, the Dungeness is now flowing closer to 180 cfs — the minimum flow biologists say will support salmon in the long-term this time of year.

Since we can’t guarantee rain showers will arrive when we need them, the community must do everything else possible to manage water for farms, people and fish.

There are few things quite like a salmon run to bring local people together in cooperation when help is needed, and in celebration when we can.

Key stakeholders implementing improvements benefiting salmon and our community include: Clallam Conservation District; Jamestown S’Klallam Tribe; Clallam County; North Olympic Lead Entity for Salmon; Washington Department of Fish & Wildlife; North Olympic Land Trust; North Olympic Salmon Coalition; Olympic National Forest, and Washington Water Trust.

Funding largely comes from these entities and landowners matching grants from the Salmon Recovery Funding Board, Puget Sound Partnership, Washington Department of Ecology and the Northwest Straits Commission.

Geek moment

It’s important to clarify that all flow numbers reported in this article pertain to the upper Dungeness River above irrigation diversions and before the inflow of several tributaries. At the Dungeness River’s mouth, the net flow — after gains and losses — can be 50 cfs less in late summer.

On the water calendar, the 2021 cycle of snow stored in the mountains and moisture stored in the soil starts tomorrow, Oct. 1. Along with that milestone, I have decided October 2020 will be my last monthly Water Column. The Gazette agreed that I can continue the commentary started five years ago, but I will shift to a routine that has more relevance to the water cycle than every four weeks.

Totals for the 2020 Water Year (Oct. 1, 2019-Sept. 30, 2020)

• Rain in Sequim at the Sequim 2E weather station (sea level): Total rainfall = 20.7 inches; High temperature = 83 degrees Fahrenheit on Aug. 15; Low = 20 degrees Fahrenheit in November.

• Cumulative precipitation at the Dungeness SNOTEL station (elev. 4,010 ft.) = 38 inches (85 percent of normal) and 2 inches of new snow!

• River flow at the USGS gage on the Dungeness River (Mile 11.2): Highest max daily mean = 1,880 cfs on Feb. 1; lowest daily mean = 90.5 cfs on Sept. 22; range for the past month = 90-500 cfs.

• River flow at the state Ecology gage (Mile 0.8) = 150 cfs.

• Bell Creek flow entering Carrie Blake Park = 0 cfs (even after the deluge!); at Washington Harbor = 2-3 cfs.

Ann Soule is a hydrogeologist immersed in the Dungeness watershed since 1990, now Resource Manager for City of Sequim. Any opinions expressed are those of the author and do not necessarily represent policies of her employer. Reach her at columnists@sequimgazette.com or via her blog at www.watercolumnsite.wordpress.com.