Lakes - Clarity - Trends

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Go to Section:
1. Overview
2. Data Quality
3. Data Organization
4. Coordinate System
5. Attributes
6. Distribution - Get Data
7. Metadata Reference

Section 1 Overview
Originator Natural Resources Research Institute, Minnesota Pollution Control Agency
Title Lakes - Clarity - Trends
Abstract This data layer indicates trends in lake clarity based on Secchi disk measurements. It was developed by the Natural Resources Research Institute using data from the Minnesota Pollution Control Agency. A Secchi disk measures water transparency or clarity and indicates the amount of light penetration into a lake. Secchi depth also provides an indirect measure of the amount of suspended material, algae or sediment, in the water. The trend analysis, which shows both the presence or absence and direction of a significant trend, was performed using a Seasonal Mann Kendall statistical test. Lake water clarity must change more than half a foot (0.15 meters) per decade to be considered a detectable change, or trend. The analysis was based on 47 years of data (1972-2019). Long-term transparency monitoring provides a cost-effective, valuable basis for detecting trends in water quality. Generally, the sooner water-quality problems are detected, the easier and less expensive it is to restore the lake to its previous state.
Purpose
Time Period of Content Date
Currentness Reference
Progress
Maintenance and Update Frequency Annually
Spatial Extent of Data
Bounding Coordinates -97.141765
-89.915627
49.404474
43.440014
Place Keywords
Theme Keywords
Theme Keyword Thesaurus
Access Constraints
Use Constraints
Contact Person Information Kristi Nixon, GIS Specialist
University of Minnesota, Natural Resources Research Institute
5013 Miller Trunk Highway
Duluth, MN  55811
Phone: 218-788-2645
Email: knixon@d.umn.edu
Browse Graphic None available
Associated Data Sets

Section 2 Data Quality
Attribute Accuracy
Logical Consistency
Completeness
Horizontal Positional Accuracy
Lineage

Section 3 Spatial Data Organization (not used in this metadata)

Section 4 Coordinate System
Horizontal Coordinate Scheme Universal Transverse Mercator
UTM Zone Number 15
Horizontal Datum NAD83
Horizontal Units meters

Section 5 Attributes
Overview
Detailed Citation
Table Detail:
lake_trends
Field NameValid ValuesDefinitionDefinition Source
FID
-
Internal feature number.Esri
Shape
-
Feature geometry.Esri
dowlknum
-
pw_basin_n
-
acres
-
INSIDE_X
-
INSIDE_Y
-
in_lakefin
-
lake_id
-
lake_name
-
nameformul
-
lakename
-
loc_major_
-
record_len
-
obs
-
mean_slope
-
mean_p_val
-
mean_huc_s
-
mean_huc_p
-
deta_slope
-
lake_ly
-
lake_ly_me
-
huc8_ly
-
huc8_ly_me
-
delta_ly_m
-
start_date
-
simple
-
trend_dire
-
dow
-
dow1
-
ObjectID
-


Section 6 Distribution
Publisher Natural Resources Research Institute (NRRI)
Publication Date 12/08/2020
Contact Person Information ,


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Phone:
Email:
Distributor's Data Set Identifier
Distribution Liability
Ordering Instructions
Online Linkage None available

Section 7 Metadata Reference
Metadata Date
Contact Person Information ,


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Phone:
Email:
Metadata Standard Name
Metadata Standard Version
Metadata Standard Online Linkage


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