September 2005 CH2M HILL & Air Sciences

Sand Mass Trends at Great Basin CSCs, ‘00-’05Owens Lake Dust Mitigation ProjectOwens Lake Dust Mitigation Project

Sand Mass Trends at Great Basin CSCs, ‘00-’05Owens Lake Dust Mitigation ProjectOwens Lake Dust Mitigation Project

Los Angeles Department of Water & PowerLos Angeles Department of Water & PowerCH2M HILL and Air SciencesCH2M HILL and Air SciencesLos Angeles Department of Water & PowerLos Angeles Department of Water & PowerCH2M HILL and Air SciencesCH2M HILL and Air Sciences

Bishop, September 28-29 2005Bishop, September 28-29 2005

Bishop, September 28-29 2005Bishop, September 28-29 2005

September 2005 CH2M HILL & Air Sciences

Goal of Analysis

• To examine spatial and temporal trends in the District sand mass collections, in light of construction activities on the lake bed

September 2005 CH2M HILL & Air Sciences

Data

• Data provided by District,– Jan 2000-July 2005

• Data summarized by year & month

• CSC locations categorized by location and/or control status

September 2005 CH2M HILL & Air Sciences

Factors Considered

• Meteorology

• Dust Control Measures (DCMs)

• Construction activities

September 2005 CH2M HILL & Air Sciences

Meteorology

• Windspeed

• Precipitation

• Temperature & Relative humidity

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

Meteorology: Results

• Wind speed in ’00-’05 similar to long term trend

• Wind speed similar during all construction phases

• Precipitation variable by year• Temperature and relative humidity

similar to long term trend

September 2005 CH2M HILL & Air Sciences

Base

Map

September 2005 CH2M HILL & Air Sciences

Construction Periods

• Pre-construction 1/00-10/00• NSS construction 11/00-12/01• Managed Vegetation 1/02-8/02• Phase 2 shallow flood 9/02-4/03• Interim (no activity) 5/03-8/03• Phase 3 construction 9/03-9/04• Phase 4 shallow flood 10/04-7/05

September 2005 CH2M HILL & Air Sciences

Analysis of Sand Mass Trends

• Two levels of Analysis:1. Trends by CSC category

2. Trends by individual CSCs

September 2005 CH2M HILL & Air Sciences

Sand Mass Trends by Category

• High throughout entire period – Shallow Flood Phase 4 and 5– Keeler Dunes

• High initially, decrease with DCMs– NSS Zone 2– Managed Vegetation– Shallow flood Phase 2

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

Sand Mass Trends by Category

• High initially, construction increase– NSS Zone 1

• Low initially, construction increase– 2002-2004 SCA

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

Results by CSC Group

• Analysis indicates increased sand mass over time due to construction activities

• However, trends in sand mass are unique on a CSC by CSC basis

September 2005 CH2M HILL & Air Sciences

Construction Evidence by CSC

• Distance to construction activity

• Timing of construction activity

• Wind speed and precipitation

September 2005 CH2M HILL & Air Sciences

Results

Map

September 2005 CH2M HILL & Air Sciences

September 2005 CH2M HILL & Air Sciences

Results: By individual CSCs

Evidence Category # Cells %

• Unlikely, low sand mass 16 12• Unlikely, high sand mass 39 28• Inconclusive 29 21• Possible evidence 10 7• Strong evidence 44 32

Total 138

September 2005 CH2M HILL & Air Sciences

Results: ’02-’04 SCA Cells only

Evidence Category # Cells%

• Inconclusive 5 15

• Possible evidence 7 20

• Strong evidence 21 65

Total 33

September 2005 CH2M HILL & Air Sciences

Sand mass affected by:

• Meteorology: No

• DCM: Yes

• Construction: Yes

September 2005 CH2M HILL & Air Sciences