# Presentation: 079970

## Changes in Suspended Sediment and Associated Trace Element Concentrations During a Storm Event 

**Arkansas River near Portland, Colorado, Downstream from Leadville, 6/29/87**

## Slide 2

## Slide 3

## USGS National Field Manual Available in Hard Copy or on the Web at:http://water.usgs.gov/owq/FieldManual/

## Total Phosphorous Concentration versus DischargeOhio River at Greenup Dam, KY, WY97 - 99

## Total Phosphorous Load Estimates: by Sampling Frequency and MethodOhio River at Greenup Dam, KY, WY97 - 99

- 20%

- Monthly+High

- Sampling

- Difference in Load Estimate, in percent

- 10%

- 0%

- -10%

- -20%

- -30%

- -40%

- -50%

- -60%

- Monthly

- Bimonthly

- Quarterly

- Ratio Estimation

- Regression

## Key Components of Models

**Point Sources**
**Areal Contributions**
**Ground water**
**Surface runoff**
**Atmospheric deposition**
**Transport Processes**
**Loss Processes**

## NADP-National Trends Network

**USGS Supported Sites**
**Non-USGS Supported Sites**

## National Atmospheric Deposition Program

**Interagency approach to environmental monitoring**
**Over 100 federal, state and local organizations sponsor sites**
**The USGS supports:**
**73 of the 226 National Trends Network sites**
**5 of the 56 Mercury Deposition Network sites **

**Data at http://bqs.usgs.gov/acidrain**

## Trends in Nitrate in Precipitation 1981-1998

**Notes:**
Looking at the isopleths of 1998 nitrate concentration we observe nitrate ranges up to  30 microequvilants per liter over the same areas of the east receiving the maximum sulfate deposition. 

Trends in precipitation chemistry for nitrate confirm the emission estimates with very few sites exhibiting either a positive or negative trend. 

## Trends in Ammonium in Precipitation 1981-1998

**Notes:**
1998 wet deposition patterns are very different for ammonium versus sulfate and nitrate. Concentrations range from less than 5 ueq/l in the west and some areas of the east to over 40 ueq in areas of the mid-west.

 Maximum concentrations of ammonium deposition occur in the Mid-western United States where the predominate land use is crop and animal agriculture. 

## Key Components of Models

**Point Sources**
**Areal Contributions**
**Ground water**
**Surface runoff**
**Atmospheric deposition**
**Transport Processes**
**Loss Processes**

## Susquehanna River at Harrisburg, PA

**Susquehanna River at Harrisburg, PA**

## NWIS Web site

## Daily Discharge ValuesHarrisburg, PA

**Daily Discharge Values****Harrisburg, PA**

## Streamflow Statistics

**USGS regression equations**
**Large effort by users to determine basin characteristics accurately – need to make it efficient**
**Prototype system: Massachusetts Streamstats**

## Regression Equations

**Regression equations take the form:****	****Q****100**** = 0.471A****0.715****E****0.827****SH****0.472**
**Drainage area is used in nearly all equations**
**Other common variables include:**
**Basin slope, relief, or mean elevation**
**Precipitation (mean annual; 2-year, 24-hour)**
**Stream length or slope**
**Land use (forest, wetland, impervious, water)**
**Basin shape or orientation**
**Soils or surficial geology**

## Site Selection for Low-Flow Analysis

## Example Output for Ungaged Sites 

## Example Output for Ungaged Sites, cont’d