Lake Lashane IA 05-GRA-1374

Decatur County S4T67NR27W 2 mi. WNW of Lamoni.

Open Data Collection Period Modal

For purposes of developing stream/river water quality assessments for integrated reporting, three years of water quality data are typically used for both conventional pollutant parameters (e.g., indicator bacteria) and the less frequently monitored toxic parameters (e.g., toxic metals). Since the 2004 IR cycle, DNR has used a three-year data gathering period for streams, rivers, and beaches. For most assessments, the use of three years of data increases the number of samples upon which the decision on use support is based and helps address the problem of weather-related year-to-year fluctuations in water quality.

Due to the lower sampling frequency in Iowa’s ambient lake, biological, fish kill, and fish tissue monitoring programs, five years of data are used for developing IR assessments and for identifying Section 303(d) listings.

Data Type	Data Timeframe
Beach Sampling Data	CY 2014 - 2016
Stream/River Water Quality Data	CY 2014 - 2016
Lake Water Quality Data	CY 2012 - 2016
Biological Sampling Data	CY 2012 - 2016*
Fish Kill Data	CY 2012 - 2016
Fish Tissue Sampling Data	CY 2012 - 2016
Continuous Dissolved Oxygen Sampling Data	CY 2012 - 2016
*Biological sites sampled in both 2011 and 2015 were also assessed.

Open Segment Map
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Cycle: 2018
Release Status: Final
Overall IR: 3 - Insufficient data exist to determine whether any designated uses are met.
Trophic: Unknown
Trend: Unknown
Created: 6/11/2019 1:14:13 PM
Updated: 6/11/2019 1:16:17 PM

Use Support

Class A1

Recreation - Primary contact

Not Assessed

Class BLW

Aquatic Life - Lakes and wetlands

Not Assessed

Class C

Drinking Water -

Not Assessed

Class HH

Human Health -

Not Assessed

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 (primary contact recreation) uses, Class B(LW) aquatic life uses, and the fish consumption uses remain "not assessed" due to the lack of information upon which to base an assessment. The Class C (drinking water) uses is assessed as not assessed The source of data for this assessment is the results of the Iowa Voluntary Atrazine Monitoring Program conducted in 2000 by Syngenta Crop Protection, Inc. This is the same assessment as that developed for previous assessment/listing cycles.

Assessment Explanation

The Class A1 and Class B(LW) uses remain not assessed due to the lack of water quality information needed to assess these uses.

The Class C (drinking water) uses are considered "not assessed" due to the lack of information upon which to base an assessment. The previous assessments of the Class C uses at this lake ["fully supported"] were based on results of sampling conducted by Syngenta "Iowa Voluntary Atrazine Monitoring Program" in 2000. However, because these data are now considered too old (greater than ten years) to accurately characterize current water quality conditions, these uses are now considered "not assessed."

Monitoring and Methods

Assessment Key Dates

3/6/2000

Fixed Monitoring Start Date

10/30/2000

Fixed Monitoring End Date

Methods

270

PWS chemical monitoring (ambient water)