Skip to main content

APPLICATION OF A LINKED WATER QUALITY RESPONSE MODEL FOR ESTABLISHING NUTRIENT CRITERIA FOR THE CALIFORNIA OAK AND CHAPARRAL SUB-ECOREGION

Buy Article:

$9.50 plus tax (Refund Policy)

Or sign up for a free trial

A current regulatory challenge is defining appropriate nutrient criteria that will protect the designated uses of a waterbody consistent with ecoregional characteristics. EPA Region IX has initiated a pilot study focusing on Sub-ecoregion 6 (California oak and chaparral).

Determining criteria requires information on both loads and responses. Criteria should not be less than natural background; neither should they be set at levels lower than those associated with a risk of degradation. In many cases, target nutrient levels may be “inherited” from downstream waterbodies that are likely to be more stringent than the concentration target needed to prevent impairment within the stream itself. A set of linked loading, transport, and response models were used to translate the potentially more stringent receiving water standards to upstream watershed export.

The USDA Soil and Water Assessment Tool (SWAT) model (Arnold et al., 1990) was used to simulate background nutrient export from headwater streams. Modeling effort focused on developing vegetation and other geographical input for SWAT. A validation exercise was conducted with six watersheds, corresponding monitoring data, and several past modeling results. The default biomass simulations required considerable adjustment, and the adjustments did not provide reasonable biomass estimates for all vegetation types. The validation results indicate that the model must be calibrated for use at the watershed level but that SWAT can provide relative comparisons among different natural communities in Ecoregion 6.

SWAT and the USGS Spatially Referenced Regressions On Watershed Attributes (SPARROW) model (Smith et al., 1997) were used to predict watershed loading and stream transport, and BATHTUB models were used for estimating lake response to nutrients (Walker, 1996). The results of the modeling analysis are estimates of natural watershed loading rates and instream nutrient concentrations that are consistent with ecoregional characteristics. The estimates provide a baseline from which to evaluate conditions where designated uses should be fully realized and allow decision-makers to discriminate water quality impacts that are due to nutrient over-enrichment.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Document Type: Research Article

Publication date: 2004-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more