Amana Lily Pond IA 02-IOW-636

Assessment Comments

Assessment remains based on information from the IDNR Wildlife Bureau and on information from an NRCS study.

Basis for Assessment

SUMMARY:  The Class B(LW) aquatic life uses are assessed (evaluated) as "fully supported” based on information from the IDNR Wildlife Bureau.   The fish consumption uses remain "not assessed" due to the lack of water quality information upon which to base an assessment.   Due only to a change in IDNR's assessment/listing methodology, the 2004 assessment of the Class B(LW) aquatic life uses ["fully supporting / threatened" (minor impacts)] is changed to "fully supporting".   Other than this change in methodology, this new (2006) assessment is the same as that developed for the previous (2004) assessment/listing cycle (not impaired) and does not reflect any known change in water quality.

EXPLANATION:  The aquatic life uses are assessed as "fully supported" based on information from the Iowa DNR Wildlife Bureau.   At the recommendation of U.S.  EPA Region 7, IDNR's 2006 assessment/listing methodology was changed to eliminate use of the "fully supported/threatened" (not impaired) category.   Thus, previous assessments identified as "fully supported/threatened" (not impaired) were changed to "fully supported" for the 2006 assessment/listing cycle.   This change does not alter the 2004 assessment:  this waterbody remains in IR Category 2a.   The assessment developed for the 2004 assessment/listing cycle is included below:.

The Class B(LW) aquatic life uses are assessed as "fully supported threatened" based on results of a recent (2002?) study by the Natural Resources Conservation Service.   A watershed analysis was completed by the NRCS in cooperation with the Amana Society as part of a Watershed Protection Development Grant from the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation.   This report indicates that sediment delivery from the watershed is not significant, and that any shoreline erosion likely stays near the edge of the pond.   The upland watershed of the wetland is not large enough to adequately supply and maintain open water on a yearly basis, and it is thought that the millrace off the Iowa River is the major supply of water through seepage to the wetland.   Based on this new information, siltation is not considered to impair the aquatic life uses of this wetland.   Thus, the degree of support of the aquatic life uses of this wetland is upgraded from "partially supported" (see assessments for previous reports above) to "fully supported / threatened."  The Section 305(b) assessment category for this wetland is "evaluated" versus "monitored."   In terms of Section 305(b) reporting, "monitored assessments" are based primarily on recent, site-specific ambient monitoring data and thus have relatively high confidence.   IDNR considers waterbodies identified as "impaired" based on "monitored assessments" as candidates for the state's Section 303(d) list.   "Evaluated assessments" are those based on data older than five years or other than site-specific ambient monitoring data (e.g., modeling studies or questionnaire surveys of fish and game biologists [=best professional judgement]) and thus have relatively lower confidence.   IDNR does not consider waterbodies identified as "impaired" based on "evaluated assessments" as candidates for the state's Section 303(d) list.  

Fish consumption uses remain "not assessed."  In general, Iowa wetlands are not managed for recreational fisheries; thus, fish contaminant monitoring is not typically conducted at these waterbodies.