usgs-data-download

Download water level data from USGS using the dataretrieval package. Use when accessing real-time or historical streamflow data, downloading gage height or d...

Security Scan

The skill is an instruction-only guide that coherently documents using the Python dataretrieval package to download USGS streamgage data; its requirements and instructions match its stated purpose and request no unrelated credentials or system access.

Purpose & Capability

Name and description match the content: the SKILL.md explains how to use the dataretrieval package to fetch USGS gage data (instantaneous and daily), including code examples and parameter codes. Nothing requested is unrelated to downloading USGS data.

Instruction Scope

Runtime instructions are narrowly scoped to installing dataretrieval, calling nwis.get_iv/get_dv/get_info, handling empty results, and rate-limiting. The guide does not instruct reading unrelated files, accessing environment variables, or sending data to unexpected endpoints.

Install Mechanism

There is no platform install spec (instruction-only), but the guide tells the user to run `pip install dataretrieval`. This is expected for a Python-based HOWTO; be aware pip installs code from PyPI (unreviewed) — consider using a virtualenv, pinning a version, and reviewing the package source before installation.

Credentials

The skill declares no required environment variables, credentials, or config paths and the instructions do not reference any secrets. Network access to USGS endpoints is required, which is appropriate for the stated purpose.

Persistence & Privilege

Skill is instruction-only with no install-time persistence requested and always:false. It does not request permanent presence or modify other skills or system-wide configurations.

Assessment

This guide appears coherent and appropriate for downloading USGS data. Before using it: run pip install in an isolated virtualenv, pin or review the dataretrieval package/version you install, be aware that downloads can be large and USGS may rate-limit requests (add delays or split date ranges), and verify station IDs and date ranges to avoid empty downloads. No credentials are required by the guide.

USGS Data Download Guide

Overview

This guide covers downloading water level data from USGS using the dataretrieval Python package. USGS maintains thousands of stream gages across the United States that record water levels at 15-minute intervals.

Installation

pip install dataretrieval

nwis Module (Recommended)

The NWIS module is reliable and straightforward for accessing gage height data.

from dataretrieval import nwis

# Get instantaneous values (15-min intervals)
df, meta = nwis.get_iv(
    sites='<station_id>',
    start='<start_date>',
    end='<end_date>',
    parameterCd='00065'
)

# Get daily values
df, meta = nwis.get_dv(
    sites='<station_id>',
    start='<start_date>',
    end='<end_date>',
    parameterCd='00060'
)

# Get site information
info, meta = nwis.get_info(sites='<station_id>')

Parameter Codes

Code	Parameter	Unit	Description
00065	Gage height	feet	Water level above datum
00060	Discharge	cfs	Streamflow volume

nwis Module Functions

Function	Description	Data Frequency
nwis.get_iv()	Instantaneous values	~15 minutes
nwis.get_dv()	Daily values	Daily
nwis.get_info()	Site information	N/A
nwis.get_stats()	Statistical summaries	N/A
nwis.get_peaks()	Annual peak discharge	Annual

Returned DataFrame Structure

The DataFrame has a datetime index and these columns:

Column	Description
site_no	Station ID
00065	Water level value
00065_cd	Quality code (can ignore)

Downloading Multiple Stations

from dataretrieval import nwis

station_ids = ['<id_1>', '<id_2>', '<id_3>']
all_data = {}

for site_id in station_ids:
    try:
        df, meta = nwis.get_iv(
            sites=site_id,
            start='<start_date>',
            end='<end_date>',
            parameterCd='00065'
        )
        if len(df) > 0:
            all_data[site_id] = df
    except Exception as e:
        print(f"Failed to download {site_id}: {e}")

print(f"Successfully downloaded: {len(all_data)} stations")

Extracting the Value Column

# Find the gage height column (excludes quality code column)
gage_col = [c for c in df.columns if '00065' in str(c) and '_cd' not in str(c)]

if gage_col:
    water_levels = df[gage_col[0]]
    print(water_levels.head())

Common Issues

Issue	Cause	Solution
Empty DataFrame	Station has no data for date range	Try different dates or use get_iv()
get_dv() returns empty	No daily gage height data	Use get_iv() and aggregate
Connection error	Network issue	Wrap in try/except, retry
Rate limited	Too many requests	Add delays between requests

Best Practices

• Always wrap API calls in try/except for failed downloads
• Check len(df) > 0 before processing
• Station IDs are 8-digit strings with leading zeros (e.g., '04119000')
• Use get_iv() for gage height, as daily data is often unavailable
• Filter columns to exclude quality code columns (_cd)
• Break up large requests into smaller time periods to avoid timeouts