Hannen Lake IA 02-IOW-704

Benton County S34T82NR11W 4 mi SW of Blairstown.

This is a Legacy Assessment. Prior to 2004, assessments were developed under a methodology that pre-dated the Integrated Report guidelines.

Assessment Cycle

1992

Result Period

1988 - 1990

Designations

Assessment Type

Monitored

Integrated Report

Category 0

Trophic

Eutrophic

Trend

Improving

Legacy ADBCode

IA 02-IOW-01810-L_0

Overall Use Support

Threatened

Aquatic Life Use Support

Threatened

Fish Consumption

Not assessed

Primary Contact Recreation

Threatened

Documentation

Assessment Comments

Assessment is based on results of UHL Iowa Lakes study in 1990.

Basis for Assessment

Assessment changed from PS to FST. Means of P, NO3, Chl a, and TSS from 1990 show no special WQ problems*. Lake was also assessed as part of UHL Iowa lakes study in 1990. This study showed no decrease in depth due to siltation and no WQ problems. Thus, assessment was upgraded from PS to FST. *Average levels of all these parameters were better than overall means for the 96 lakes sampled in 1990; i.e., better than average water quality. Sedimentation rate (2.1 cm/yr) and life expectancy (131 years) are better than the typical SPO impoundment. Levels of use reported by Bachmann et al. are rel high for fishing and rel low for swimming. DSC (1991: 4) reports that (1) recreational uses have not been impaired by NPSP and (2) WQ trend is stable.