Potential target method 4 using density and eto factors
Download
1 / 37

Potential Target Method 4 Using Density and ETo Factors - PowerPoint PPT Presentation


  • 178 Views
  • Uploaded on

Potential Target Method #4 Using Density and ETo Factors. U4 Technical Subcommittee Meeting August 25, 2010. Tom Hawkins DWR. Tim Barr of Western Municipal Water District proposed a target method that uses variances in urban densities and ETo within a hydrologic region.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Potential Target Method 4 Using Density and ETo Factors' - meghan


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Potential target method 4 using density and eto factors l.jpg

Potential Target Method #4Using Density and ETo Factors

U4 Technical Subcommittee Meeting

August 25, 2010

Tom Hawkins

DWR


Slide2 l.jpg

  • Tim Barr of Western Municipal Water District proposed a target method that uses variances in urban densities and ETo within a hydrologic region.

  • This presentation will be on the analysis performed with the purpose to determine if there is a relationship between these factors and water use.


Slide3 l.jpg

  • The target setting equation for this method: target method that uses variances in urban densities and ETo within a hydrologic region.

    Agency 2020 GPCD Target

    =

    [(HR Target – 55)

    X

    (Agency ETo/HR ETo)

    X

    (HR Urban Density/Agency Urban Density)]

    +

    55


Slide4 l.jpg

  • Primary factor affecting per capita water use is outdoor water use.

    • Outdoor water use can be affected by urban density (lower densities would have more irrigated landscape per person).

    • Outdoor water use can also be affected by weather (hotter/drier climates would have higher ET rates).


Slide5 l.jpg

  • For this analysis, water use.

    • Urban densities were developed using DWR population data and Dept of Conservation’s urban GIS data.

    • For weather, normal year annual ETo were used. Water use was DWR’s data from Calif Water Plan Update.


Slide6 l.jpg

  • GIS layers used: water use.

    • 2006 Urban Boundaries (From DOC Farmlands Mapping)

    • Normal Year Annual ETo (DWR and UC)

    • Detailed Analysis Units (DWR)

  • Tabular Data Used:

    • 2005 Urban Water Use by DAU (DWR)

    • 2005 Population by DAU (DWR)




Slide9 l.jpg

Urban Areas (DOC) water use.



Slide11 l.jpg


Slide12 l.jpg


Slide13 l.jpg

  • I reviewed the DAU data for QA/QC. Boundaries, were all intersected to create a new layer.

    • I visually reviewed those DAU’s with high densities (higher than Orange DAU at 11.07 people/acre). It was apparent urban acreage were missing, either totally for some DAU’s, or only a portion of the urban areas were delineated within a DAU. Those DAU’s were removed.

    • It was also clear that DAU’s with low populations had unreasonably high or low densities (acreage or population problems) and removed DAU’s with a population of less than 5,000.


Slide14 l.jpg

  • The data from the DAU data table were separated out by HR. Boundaries, were all intersected to create a new layer.

  • For each HR, the following data were used:

    • Population for each DAU, and for the HR

    • Urban acreage for each DAU, and for the HR

    • Urban water use for each DAU, and for the HR

    • ETo for each DAU, and for the HR


Slide15 l.jpg

  • Urban densities by DAU and by HR were calculated: Boundaries, were all intersected to create a new layer.

    • Population/Urban acreage

  • The Density Factor was calculated:

    • HR urban density / DAU urban density

  • The ETo Factor was calculated:

    • DAU annual ETo/HR annual ETo

  • The final Density-ETo Factor was calculated:

    • Density Factor X ETo Factor


Slide16 l.jpg

  • Urban per capita water use was calculated for each DAU using this equation:

    • DAU Volume of urban water use/DAU Population

  • A scatter chart was created for each HR using DAU per capita water use on the Y axis, and the DAU Density-Eto Factor on the X axis.

  • A regression trendline was added, along with the regression equation and R squared.


Slide18 l.jpg

North Coast HR this equation:

Density-ETo Factor


Slide19 l.jpg

San Francisco Bay HR this equation:


Slide20 l.jpg

Central Coast HR this equation:


Slide21 l.jpg

South Coast HR this equation:


Slide22 l.jpg

Sacramento River HR this equation:


Slide23 l.jpg

San Joaquin River HR this equation:


Slide24 l.jpg

Tulare Lake HR this equation:


Slide25 l.jpg

South Lahontan HR this equation:


Slide26 l.jpg

Colorado River HR this equation:




Slide29 l.jpg

SR, SJR, and TL HR’s this equation:



Slide31 l.jpg

  • The results: this equation:

    • The data analysis did not result in a good regression relationship.

  • Does this disprove the concept?

    • Do not know

    • The datasets used may not be of high enough quality and coverage to be able to show a relationship.


Slide32 l.jpg

  • ETo this equation:

    • Normal year was used, not 2005 data

    • The GIS layer used did not completely cover the whole coastline, where some urban acreage were not included in the analysis because of no ETo.

    • How accurate is the normal year ETo map? There was not a huge amount of data available in urban areas of the state when developed.

    • Is annual ETo the correct factor to use? Would the addition of effective precipitation improve the factor?


Slide33 l.jpg

  • Water Use this equation:

    • The data used is based on voluntarily provided water use data by water agencies.

    • Not all provide data, some DAU’s probably are not represented by a water agency.

    • The data used for this analysis is all urban water use, including that supplied by water agencies and self supplied water (private wells).


Slide34 l.jpg

  • Urban Area this equation:

    • DWR’s land use survey data a point-in-time dataset, and the urban areas would include data from the late 80’s. We don’t have digital surveys in much of the coastal urban areas.

    • DOC’s urban layer is missing some significant areas (Los Angeles County, San Francisco, and portions of other counties.

    • DOC’s data does show that in some areas, rural (low density) urban areas are delineated, and not in other areas.

    • The layer is for all urban, not just that in water agency boundaries.


Slide35 l.jpg

  • Population this equation:

    • DWR has to develop population estimates by DAU. This is done using Census and DOF data and recent aerial imagery. Always room for improvement.


Slide36 l.jpg


Slide37 l.jpg

  • Questions/Comments? significant work to be able to come up with a supportable and agreeable urban delineation (acreage) by hydrologic region.


ad