State Water Resources Control Board Considering Adoption of Revised Emergency Regulations 

As California heads into a third consecutive dry year, the State Water Resources Control Board is proposing the adoption of a revised emergency regulation for the Russian River watershed. The 2022 proposed regulation clarifies requirements, refines analyses, and addresses stakeholder feedback received over the past year.

On April 29th, the State Board notified the City that the Division of Water Rights has posted a Notice of Proposed Rulemaking, in preparation of submittal to the Office of Administrative Law, for the proposed 2022 emergency regulation online. Included in the posting are documents providing context and justification for the proposed regulation, fiscal impacts, and a copy of the proposed regulation as it will be presented to the State Water Resources Control Board for consideration at the May 10th Board Meeting. The documents are available for download at the Russian River Drought Response Webpage under the “Emergency Regulation” heading.

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City Arborist Highlights Drought Impacts on Plants and Trees

Drought conditions, or more specifically, soil water deficits, can influence the normal physiology and growth of trees and plants in many ways. For example, when a soil water deficit exists, the result may be an increase of solute concentration outside the roots compared to the internal environment of the root. Such a situation leads to reverse osmosis, i.e. a net movement of water from the cell to the soil solution. As this happens, the cell membrane shrinks from the cell wall and may eventually lead to death of the cell.

More commonly, when a water deficit occurs, soil water tends to shrink away from the interface with water-absorbing roots, creating a gap in the soil-plant-air continuum. As the plant continues to lose water via transpiration, water is drawn from root cells resulting in shrinkage of cell membranes. If these conditions persist, the integrity of the cell membrane and the living cell itself may be destroyed.

In the root system of a tree or shrub, the delicate root hairs that extend from epidermal cells and feeder roots at the extremities of the root system are responsible for the bulk of water uptake. Confined to the upper 15 inches or so of the soil profile, they are also the first part of the root system affected by dry soil conditions. With the death of root hairs, the water absorbing capacity of the plant is severely reduced which ultimately cases the tree to decline.

There are several ways to reduce drought stress to the trees and vegetation. Installation of mulch is an excellent method of retaining water while also providing beneficial nutrients to the soil during drought conditions. Mulch should be installed 3 to 4 inches deep from near (but not touching) the trunk to the edge of the dripline (or as far as is reasonable for the site). Mulch can also  helps prevent soil compaction from machinery, vehicles, or foot traffic. Finally, since tree roots do a poor job of competing with turfgrass for water and nutrients, using mulch below trees reduces the stress caused by turf.

This newsletter was prepared by City Arborist and Park Superintendent Héctor Galván.

Northern Sonoma County Air Pollution Control District 
Clean Air Expo - May 6, 2022

Clean Air Expo Event on May 6, 2022
The Northern Sonoma County Air Pollution Control District will be sponsoring a clean air exposition with Old World Winery at 850 River Road from 10AM-2PM that includes:

• Demonstrations of zero emissions electric tractors and commercial equipment for working lands. Vendors include Solectrac, Stihl, and Husqvarna.
• Local biomass innovations & solutions including new small business start-ups from the District’s Biomass Business Competition: Soil Carbon Mgt. Co. & Forestree Collective).
• Overviews of District clean air incentive programs to replace woodstoves; install EV charging; and to replace diesel equipment & vehicles. The District’s Carl Moyer and FARMER diesel replacement programs are now open through June 30, 2022.

Admission is free! See you there!