Arroyo Walls

What’s still green: Arborvitae, juniper and other evergreens, Apache plume, some rose stems, cholla, prickly pear, yuccas, Japanese honeysuckle, grape hyacinth, sweet peas, vinca, beardtongues, coral bells, sea pink, pink and yellow evening primroses, purple aster, cheat grass; new chrysanthemum and snapdragon leaves.

What’s grey, blue-grey or grey-green: Piñon, pinks, snow-in-summer, saltbush, winterfat; new yellow alyssum leaves.

What’s red: Saint John’s wort.

What’s yellow: Weeping willow branches.

What’s blooming inside: Bougainvillea and aptenia; rochea and Christmas cactus leaves tinged with red; new leaves on pomegranate and zonal geraniums.

Animal sightings: Rabbit out early Wednesday between storms. Horses down the road were unhappy with water in their paddock Friday morning: they had walked to the edge of the flooded land and were just staring when I drove by.

Weather: Warm temperatures brought more rain than snow this week, and 3" of mud on frozen ground in the drive; ice now fills many terraced beds in early morning; 10:10 hours of daylight today.

Weekly update: Architects rarely get on with the men tasked with building their designs, because too many architects lack enough training in structural engineering and the practical problems of routine work like running conduit and pouring concrete.

Gardeners can have the same problems. When Louise Beebe Wilder said she filled the joints of her stone steps "with inviting sandy loam in the hope of attracting some little green home-seeker" one wonders how long before those steps needed repair from root damage.

Similarly, when Gertrud Jekyll said the walls defining a sunken garden were built with "blocks of stone with wide joints, all laid a little sloping back, so that the whole face of the two walls lies back." and that "the wall was planted, both as it was built, and also afterwards," one wonders if she’d ever observed the damage caused by water falling back into a wall in summer or freezing under it in winter.

The men repairing the near arroyo are all too aware of the dangers of water. Near the road, on the downriver side, a pipe empties water coming through the ditches that wasn’t diverted for irrigation. That part of the arroyo is nearly twice as deep as it is on the other side of the road, and I rather suspect threatens the integrity of the road itself. I hate meeting trucks there because we’re both hugging the center.

Last summer, a new acequia outlet was installed on the upriver side that threatens the bank there. Although storm water rarely does more than wet a narrow bottom channel, an afternoon storm several years ago sent water rushing through that part of the arroyo. When I passed, the owner was out taking pictures. Soon after he offered his property for sale.

By definition, arroyo banks are soft. When water slides over the slopes leading to the river, it washes away unprotected layers between plants. Water continues to channel into the softer rivulets, washing away more dirt and gravel until a full arroyo or its feeder forms. Those walls, even if sandstone, can then be carved away by both wind and rain.

Last summer, men began stabilizing the near arroyo walls. On the upriver side, they abraded the bank to make a smooth incline, then covered it with black fabric to prevent water and seeds from getting to the soil. As if they were getting ready to stucco the bank, they next laid out two layers of mesh that resembled chicken wire, but was heavier gauge, and drove in anchoring steel angle posts.

Finally, they took large rocks, and dumped them between the layers. On the other side, the banks were so steep they needed to be terraced. There they formed stepped back rows of caged rocks.

Work on the downriver side was finished and the face of the culverts carrying water under the road was cemented over before winter. Work on the other side stopped, apparently awaiting the arrival of more 8' culverts. This week, the remaining snow, after days of rain and light snow, marked the path of water and potential destruction.

Wilder was concerned that "where time is slow to bestow its softening touch of moss and lichen, stonework in the garden is apt to have an alien, unconnected look" and believed "encouraging suitable plant life in the chinks and joints" would create "a more harmonious ensemble."

Penelope Hobhouse suggests Jekyll was concerned with the needs of terracing sloping sites, and emphasizes she said "nothing is prettier or pleasanter than all the various ways of walling, that is to say, rough wall-building without mortar, especially where a suitable kind of stone can be had locally."

Here cost, availability and function dictate the use of what we call large river rock. The rocks long ago fell from mountains to the north and have been smoothed by time. Many are granite or other hard stone, not erodible sandstone or limestone. Eventually the wire net will oxidize to the same monotonous grey. Even though the rocks may be somewhat indigenous, the treated arroyo walls will remain the alien, but necessary presences disdained by Wilder and Jekyll. However, I’d rather drive a road over a reinforced arroyo than one that’s picturesque and crumbling.

Notes:
Hobhouse, Penelope. Gertrude Jekyll on Gardening, 1983, compilation of writings by Jekyll with commentary by Hobhouse.

Jekyll, Gertrude. Wall and Water Gardens, 1901.

Wilder, Louise Beebe. Colour in My Garden, 1918, emphasis in original.

Photograph: Arroyo wall after night of rain, 22 January 2010; soft bank and local gravel are in the right foreground, the interrupted repairs to the left; the road is directly to the right.