All Things Water

October 13, 2020

Presented by:

Heather Brown (Water Quality Coordinator)

Dawn Calciano (Conservation Coordinator)

All Things Water

This presentation will cover:

Water Sources and Uses

Water System Operations and Maintenance

Water Quality

Water Conservation

Water Management Plans and Studies

Davis Water

The City of Davis historically relied on groundwater for 100% of our water supply. In June 2016, Davis began adding treated surface water from the Sacramento River to our water system.

Surface water is treated at the Woodland-Davis Regional Water Treatment Facility. The City of Davis’ allotment is 10.2 million gallons per day.

In 2019, approximately 87% of the city’s water was surface water with the remainder primarily coming from the city’s deep wells. The monthly average of surface water ranged from 63% (summer months) to 99% (winter months).

The City currently has 5 deep aquifer wells and 4 intermediate wells in operation. The intermediate wells are typically only operated to ensure they are exercised properly and as required for water quality testing.

Water System Schematic

Production Amounts per Source

Type of Source Location Production for 2019

Intermediate Well(366 to 492 feet

below ground

surface)

Well 23 0.009%

Well 24 0.014%

Well 26 0.007%

Well 27 0.000%

Deep Well(1520 to 1802 feet

below ground

surface)

Well 30 0.000%

Well 31 7.741%

Well 32 3.208%

Well 33 0.821%

Well 34 1.282%

Surface Water Point of Entry 86.918%

Water Treatment

Surface Water

Surface water is from the Sacramento River and treated at the Regional Water Treatment Facility in Woodland

Surface water is treated by a variety of treatment techniques, including flash mixing, filtration, ozonation, disinfection

Chlorine for disinfection

Ortho-phosphate for corrosion control

Groundwater

Chlorine is added for disinfection

Manganese Treatment

Well 32 – Manganese treatment onsite

Well 34 – Blending with surface water

Operations and Maintenance

Mission of the water division is to operate and maintain the water production, transmission and distribution infrastructure in order to deliver clean, reliable potable water for use by Davis citizens, and non-potable water for irrigation purposes.

Led by the Water Division Manger, there are 3 crews:

Production

Distribution

Programs

Distribution Crew

Maintains 191 miles of distribution and transmission mains

Replaces hydrants, valves, and service lines

Repairs main breaks

Conducts valve exercising and flushing operations

Supports team for other divisions

Maintains infrastructure at North Davis Meadows (NDM)

Production Crew

Operates the water system and maintains pressure

Monitors SCADA (supervisory control and data

acquisition)

Operates 3 water storage tanks and 9 groundwater wells

Coordinates deliveries of surface water from the

Regional Water Treatment Plant in Woodland

Checks chlorine residuals at well sites

Operates the North Davis Meadows

(NDM) system

Programs Crew

Monitors Aclara (meter

database)

Performs water meter

reads, testing, and

maintenance

Performs backflow

testing

Conducts continuous

use checks for single-

family residences

Conducts Underground

Service Alerts (USAs)

for water, wastewater

and stormwater

Meter Testing

Water Quality Regulations

The City is required to monitor its source water and treated drinking water for Title 22 compliance, as mandated by the California Code of Regulations.

The City operates its water system under Permit 01-09-17-PER-006. Regulated by the State Water Resources Control Board, Division of Drinking Water.

The City is required to sample certain constituents weekly, quarterly, annually, and/or tri-annually to ensure safe drinking water is delivered.

The Annual Water Quality Report provides information on detected constituents in City’s water sources

Water Quality

The delivery of surface water has significantly changed the quality

of your drinking water. Surface water contains very few metals

and is much softer than local groundwater.

The table below is a comparison of selected constituents to see

how the quality of water has changed from 2015 (solely

groundwater) to 2019 (current water supply of both surface water

and groundwater).

Water Quality Testing

The City collects:

Weekly distribution system bacteriological samples

Monthly distribution system monitoring samples (boron, hardness)

Quarterly groundwater well samples and sampling station disinfection by-products samples

Annual groundwater well samples and distribution system asbestos samples

Tri-annual residential Lead and Copper Rule samples

Unregulated Contaminant Monitoring Rule samples every 5 years

The City collects samples beyond what is required by State and Federal drinking water standards in order to better understand the quality of water being delivered.

Water Quality Upcoming

Regulations Unregulated Contaminant Monitoring Rule 5 (2023-2025)

Federal rule

Every 5 years, the US EPA creates a list of up to 30 unregulated contaminants to be monitored by public water supplies. These unregulated contaminates may be considered for regulation in the future.

Contaminants of Emerging Concern

Microplastics

SB 1422 requires the State Water Board to adopt a definition of microplasticsin drinking water, adopt a standard methodology to be used for analytical testing, and require four years of testing and reporting

Per- and Poly-fluoroalkyl Substances (PFAS)

Part of a family of chemicals routinely used in grease-proof coatings for food packaging, stain-resistant coatings for carpets/clothing/furniture, non-stick cookware, and fire-retarding foams

These substances are a concern in drinking water because of their persistence in the environment and tendency to accumulate in groundwater

Water usage in the spring/summer of 2020 has increased in

comparison to 2019.

Increased indoor water use

Shelter-in-place orders due to the global COVID-19 pandemic have likely

increased indoor water use in recent months

Increased frequency of hand washing, sanitation and clothes washing.

Dry spring

No rain in February, and less than average rain in March

Many people noticed an increase in their water usage for the spring

months due to the need for irrigation.

While we have seen an uptick in water use in recent months,

overall Davis water customers continue to be conservation-

minded, and these ongoing efforts to conserve water make a

difference.

Water Usage Updates

Conservation Tracker

Conservation Updates

City of Davis water production was 19% less in 2019 than in 2013 (State

baseline year).

The City is on target to surpass our 20% by 2020 gallons per capita day

(gpcd) State target of 172 gpcd. For 2019, the City gpcd was 125.

Long-term water use efficiency regulations were released by the state in

Spring 2018.

Weather patterns may change with dry and wet years but the City is

committed to looking at long-term efficiency.

Water Meter Upgrade Project

The City-wide Water Meter Upgrade project is now

complete.

Involved exchanging all existing water meters for

new meters with Advanced Metering Infrastructure

(AMI).

AMI allows for hourly water usage information to be

transmitted over a secure network approximately

four times per day.

AquaHawk

AquaHawk is the City of Davis’ online customer water

use portal.

Ability to set usage alerts is one of the primary benefits

of the water use portal, allowing for users to spot and

repair leaks as quickly as possible. ◦ There are no automatic alerts in AquaHawk.

Over 4,950 users currently registered.

Using AquaHawk to Assist in

Finding Leaks

Sign-in to AquaHawk

For single-family properties look for signs of continuous

water usage throughout the night.◦ Single-family residential properties typically will have some

hours of zero water usage, especially during the nighttime

hours.

◦ In AquaHawk, look for the bright blue bars (as shown below) for

actual water usage on your graph.

Checking for Leaks

Senate Bill 606 and Assembly Bill 1668 call for creation of new statewide

urban water use efficiency standards for indoor use, outdoor use and

water lost to leakage.

The State Water Board will adopt these standards by regulation no later

than June 30, 2022.

Beginning November 2023, each urban retail water agency will calculate

and report its water use objective annually.

Many details for implementing the new water use requirements will be

determined over the next several years.

New Water Use Efficiency

Standards

Water Use Objective

Many details for implementing the new water use

requirements will be determined over the next several

years.

Sustainable Groundwater

Management Act

The Sustainable Groundwater Management Act (SGMA)

requires groundwater management in priority

groundwater basins.

This includes the formation of GSAs (Groundwater

Sustainability Areas) and the development of

Groundwater Sustainability Plans (GSPs) for

groundwater basins or subbasins that are designated by

DWR as medium or high priority.

City of Davis actively participates in the Yolo Subbasin

Groundwater Agency (YSGA).

City of Davis Water Management

Plans

Integrated Water Resources Study/Plan (IWRS/P)

➢ Purpose is to identify potential water resource options available to the City and their associated costs.

➢ Last study completed in 2013.

➢ Looking into sources including: recycled water, surface water, groundwater, and irrigation only non-potable (non-drinking) water

Urban Water Management Plan (UWMP)

➢ Every five years all urban retail water agencies with over 3,000 connections are required to submit an updated Urban Water Management Plan to the Department of Water Resources (DWR).

➢ The next UWMP update is due July 1, 2021.

➢ Within UWMPs suppliers must:

o Assess the reliability of water sources over a 20-year planning time frame, describe water shortage contingency plans.

o Report progress toward meeting a targeted 20 percent reduction per-capita (per-person) urban water consumption by the year 2020.

o Discuss the use and planned use of recycled water.

Aquifer Storage and Recovery

(ASR)

ASR is the injection of treated surface water into an

underground aquifer for the purposes of storage.

The stored water is then withdrawn from the aquifer at a

later date.

Currently, the City is not capturing its full allotment of

10.2 million gallons per day of surface water in the winter

months. The City typically uses only 5 million gallons of

surface water per day during low demand months.

ASR could potentially improve the reliability of water

supplies during the summer months and improve the

quality of pumped water.

The City is currently completing an ASR feasibility study to

determine if ASR is a suitable option to expand the City’s

potable water portfolio.

City of Davis Water Utility 101

Provides an overview of the

City’s Water Utility

Includes additional

information on water rates,

water regulations, and

information on building a

resilient water utility.

Available on the city’s

website under Public Works

Utilities and Operations –

Water

Please email any questions to Water@cityofdavis.org