Rain, Rain, Please Stay AND Come Again Another Day!

Waterfall on Holstein Hill Trail, Montini Preserve

Today, the second day of an “atmospheric river” storm, I hiked the Montini and Overlook properties to check out how well the water was getting off the trails. More water was running off than I recall ever seeing before, although I had missed the October storm which by all accounts was a gangbuster.

You know it’s a major storm when the waterfall on the Holstein Hill trail on the Montini Preserve is running as it was today (see photo).

Most of the trail structures put in place to get water off the trail were working as intended, although a few need to be cleaned out or enhanced. The properties are so rocky, however, that in places water seeps from the hill above and sheets over the trail. In other words, there’s just no getting around having water on the trail, so be careful.

Building an Armored Swale

Today Jess and I (both volunteer stewards) tackled a Montini trail project that I had long planned. There was a place on the Rattlesnake Cutoff Trail where water, during heavy storms, would flow across the trail. Since the initial construction of the trail didn’t take this into account, the water would pool on the trail, leading to a long trail segment that would essentially turn into a tiny lake (see photo).

The Montini Preserve was heavily mined in the early 1900s (this property and adjoining Schocken Hill, now the Sonoma Overlook Trail, essentially paved the streets of San Francisco at the time), and there is a quarry “divot” in the hill above that collects rainwater and funnels it out to the trail. Being essentially bedrock, the water has nowhere to go but out and down. 

What the trail needed is what’s called an “armored swale,” which is essentially a channel cut into the trail that is protected by a floor of rocks to prevent erosion. I had been waiting for rain to soften the soil, as we would first need to excavate the existing rocks and in summer the ground is like concrete. It rained yesterday, so the soil was going to be about as soft as it was going to get. Also, since I knew that an “atmospheric river” was set to dump several inches of rain in a matter of a few days, now was the time to act.

So Jess and I went out today and built it. We first needed to excavate a channel across the trail, then place stones to protect from erosion, and fill in gravel and soil around the stones. Do your worst, atmospheric river; we’re ready for you!

Prepping the Trails for Rain

Since rain was predicted for today (and it came!) I headed out earlier in the week with a mattock to clear trail drainage channels, which had become clogged with rocks, leaves and miscellaneous debris since spring. Water must be guided off our trails immediately or else it will erode the trail and harm it, especially over time. Plus we don’t want the soil that gets eroded to end up in our waterways.

I also cut new ones where I thought they may be needed. Some of this work is obvious, but I know that additional work will be needed once we actually have flowing water on the trails and can see the trouble spots, where water is pooling or running down the trail.

This is just one task that the volunteer stewards group does throughout the year to keep our trails safe and well-maintained.

 

The March/April Miracle

Perhaps we could be forgiven, those of us here in Northern California, for believing that we were heading right back into drought. The amount of rain we had received through February (typically some of our heaviest precipitation months) was truly sad. But then March came, and brought more rain, and even more important, snow in the Sierra Nevada Mountains.

And then came April, which has brought a Pineapple Express storm, with reportedly more to come. Today on the trail we saw a phenomenon we only see when the runoff is truly epic — popup springs (see picture). This happens when water completely saturates the soil and finds underground channels. These channels then surface in random spots in the hillsides, spilling out to run down the hill before finding a creek to add its volume to, potentially leading to flooding downstream.

Logically, I know that this can lead to tragic consequences. But upstream, where these popup springs happen, it simply seems exciting. This is one of the reasons why I love to hike in the rain. I never let the weather stop me from hiking the trail. I put on my rain pants, parka, and waterproof shoes, and go for it. It can be an astonishing time. One day I saw a flock of turkeys running through a downpour. Several other times the creek on the Overlook was running so high I had to hike upstream to find a place to cross it. But it never fails to be exciting, at least to me.

Come enjoy the miracle, as I do. In the glorious wet. It’s only water, after all, and what you stand to gain is a lot more impactful than that.