knightsen wetland restoration project

Knightsen Wetland Restoration Project

Eagle Lane Community Meeting on August 26, 2021 at 7:00 pm

1

Knightsen Wetlands Restoration Project

Eagle Lane Neighborhood Meeting Thursday, August 26, 7:00 p.m.

Meeting Purpose • Provide a project update for immediate neighbors. • Discuss conditions related to stormwater, groundwater, and septic systems on adjacent

properties and learn more about neighbors’ concerns.

Agenda

1. Welcome and Introductions a. Welcome b. Introductions c. Agenda review

2. Project Update and Discussion a. Project purpose and development process. b. Current site and neighborhood conditions (soils, water, and groundwater;

summer and winter conditions). c. General site layout and future site functions and conditions. d. Stormwater, groundwater, and septic systems. e. Other topics or questions.

3. Next Steps a. Ongoing design and evaluation work and project planning process. b. Next meetings.

Handouts Meeting handouts are attached for discussion. Available Studies Recent and past studies are available on the project website: https://www.contracosta.ca.gov/7624/Knightsen-Wetland-Restoration-Project

Meeting Ground Rules

Civility and Respect

1. Speak honestly and clearly about your knowledge and perspective. 2. Listen openly to the knowledge and perspectives of others. 3. Be succinct and on topic. 4. Seek knowledge and understanding to resolve disagreements. 5. Ask for what you need.

2

https://www.contracosta.ca.gov/7624/Knightsen-Wetland-Restoration-Project

Byro

n Hwy

Delta Rd

Sunset Rd

Delta Rd

Eagle Ln

Poe Ln

Penny Ln

Mountain View Dr

0 2,000 4,0001,000

Feet ®

3

Site Investigation

& Design

Environmental Review & Permitting

Funding & Construction

Today

2021 2022 2023 2024 2025

Site Investigations

FinalPublic Review

Draft Env. Review

Project Design100%

Project Construction

Permitting

Funding and Contracts

Draft Env. Review 100% Design

30% 90%

Construction

Project Purpose

Estimated Timeline (subject to change)

1. Protect land from development.2. Restore natural habitat and reconnect to the Delta.3. Improve water quality discharging to the Delta.

4

Site Characterization Studies UpdateGeology & Groundwater

5

Subsurface Investigations

Ongoing• 8 new shallow wells, monitored

since 2017.

• 12 shallow borings, 6 converted to shallow wells and monitored since 2020.

• 14 cone penetrometer tests (CPTs)

• Compiled drilling records for wells surrounding the property.

• Interpretation of underground conditions for 4 cross sections.

• 12 wells sampled for water quality.

• 34 test pits across the property and soil trenching at north parcel (not shown).

6

Clay zones separate shallow groundwater from deeper groundwater where

domestic wells draw water.

7

Rainfall raises shallow groundwater levels during the wet season

Near No Name Slough

North Parcel

8

Irrigation raises shallow groundwater during the dry season.

Near Eagle Ln

Center of Property

9

Concluding Remarks on Groundwater

• Domestic wells draw from deeper groundwater that is separated by clay zones.

• Shallow groundwater is interconnected with surface water.

• Discontinuing site irrigation in the summer will lower the shallow groundwater.

• Groundwater modeling is underway to inform project design.

10

Updated Site LayoutsDrainage, Levees, and Tidal Wetlands

11

© 2021 Microsoft Corporation © 2021 Maxar ©CNES (2021) Distribution Airbus DS














N

RESTORED DUNES AND GRASSLAND

RESTORED TIDAL MARSHWITH FLOOD CONTROLLEVEE, ALKALI MEADOW

GRASSLAND & OAK SAVANNA

STORMWATER WETLAND

DELTA ROAD INLET

WATER CONTROL STRUCTURE


BYRON HIGHWAY DIVERSION

BIOSWALES WITH SEASONALWETLAND DEPRESSIONS


EAGLE LANE NO NAME SLOUGH

RESTORED DUNES AND SEASONALWETLANDS, NOT SHOWN

OVE

R F

LOW

PAT

H

T

O P

UM

P ST

ATIO

N

DELTA ROAD

BYR

ON

HIG

HW

AY

BYRON HWY DITCH

RICHARDSON DRAIN

DELTA ROAD DITCH

PUMP STATION

WET SEASON CONDITIONS DRAFT















RESTORED DUNES AND GRASSLAND

RESTORED TIDAL MARSHWITH FLOOD CONTROLLEVEE, ALKALI MEADOW,

MUTED TIDAL WETLAND



BYRON HIGHWAY DIVERSION

ALKALI MEADOW WITH SEASONALWETLAND DEPRESSIONS


EAGLE LANE NO NAME SLOUGH

RESTORED DUNES AND SEASONALWETLANDS, NOT SHOWN

OVE

R F

LOW

PAT

H

T

O P

UM

P ST

ATIO

N

DELTA ROAD

BYR

ON

HIG

HW

AY

N


DELTA ROAD INLET

BYRON HWY DITCH

RICHARDSON DRAIN

DELTA ROAD DITCH

PUMP STATION

DRY SEASON CONDITIONS DRAFT

Additional Backgroundhttps://www.contracosta.ca.gov/7624/Knightsen-Wetland-Restoration-Project

13

https://www.contracosta.ca.gov/7624/Knightsen-Wetland-Restoration-Project

Situated at the landward margin of tidal wetlands, the site offers unique wetland restoration opportunities.

Qs = Quaternary Sand(upper Pleistocene)

14

knightsen wetland restoration project

Documents