### Updates to the Suspended Sediment SPARROW Model Developed for Western Oregon and Northwestern California

By: Daniel R. Wise**

                            https://doi.org/10.3133/sir20185156

#### Links

-                                                                                                                             Document:                                                                                                                                                                                                                                                  **Report**                                                                                                     (16.7 MB pdf)                                                                                                                                     
- Appendix:  **Appendix 1**                            (34 KB xlsx)                        
- Data Release:  **USGS data release**  - Predictions from the updated SPARROW suspended sediment models developed for western Oregon and northwestern California
- Download citation as:  RIS                         |                         Dublin                            Core

#### Abstract

First posted December 21, 2018

**For additional information, contact:**
Director, Oregon Water Science CenterU.S. Geological Survey2130 SW 5th AvenuePortland, Oregon 97201

A SPARROW (SPAtially Related Regressions On Watershed attributes) model that was previously developed for western Oregon and northwestern California was updated using advancements in the SPARROW software and refinements to the input data. As was the case for the original model calibration, the updated models used the NHD Plus Version 2 as a hydrologic framework and relied on the same estimates of long-term mean suspended-sediment loads and watershed attributes. The updated calibration results indicated that two different SPARROW models were possible—one model from which sediment sources were represented by local lithology and one from which sediment sources were represented by generalized land-cover classes; precipitation, catchment slope, wildfire disturbance, and sediment loss in impoundments were significantly correlated with suspended-sediment loads in both models. The updated models also included a method to compensate for the bias introduced by using total suspended solids to represent suspended sediment in the calibration dataset—a feature that was not available during the original model calibration. The effect of this feature was an overall increase in estimated suspended-sediment loads. Although the lithology- and the land-cover based models used different landscape properties to describe sediment sources, each could be useful in specific applications. The lithology-based model provides more accurate estimates of suspended-sediment load, but the land-cover based model allows water-quality managers to estimate how much in-stream suspended-sediment load originates in areas with extensive development compared to the load that originates in areas with relatively little human impact.

#### Suggested Citation

Wise, D.R., 2018, Updates to the suspended sediment SPARROW model developed for western Oregon and northeastern California: U.S. Geological Survey Scientific Investigations Report 2018–5156, 23 p., https://doi.org/10.3133/sir20185156.

ISSN: 2328-0328 (online)

#### Study Area

#### Table of Contents

- Abstract
- Introduction
- Description of the Modeling Domain
- Methods
- Calibration Results and Predictions
- Interpretation of Results from the Updated SPARROW Suspended Sediment Models
- Differences Between the Original and Updated Suspended Sediment SPARROW Models
- Application of the Updated Suspended Sediment SPARROW Models
- Summary
- References Cited
- Appendix 1. Summary of Calibration Data for the Updated Suspended Sediment SPARROW Models Developed for Western Oregon and Northwestern California

Part or all of this report is presented in Portable Document Format                        (PDF). For best results viewing and printing PDF documents, it is recommended that you download                        the documents to your computer and open them with Adobe Reader. PDF documents opened from your                        browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge. More information                        about viewing, downloading, and printing report files can be found at the common download problems FAQ.

Part of this report is presented in Microsoft Excel format (XLSX); the                        latest version of Excel Viewer is required to view it. Download the latest version of Excel Viewer, free                        of charge.