Add SiteTypeCode and StatisticCode enums for waterdata parameters

Exposes discoverable constants for the `site_type_code` and `statistic_id`
parameters so callers get IDE autocompletion without breaking any existing
string-based usage (both enums extend `str`).

Closes #98

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: thodson-usgs

dataretrieval/waterdata/__init__.py

@@ -25,6 +25,7 @@
     get_stats_por,
     get_time_series_metadata,
 )
+from .enums import SiteTypeCode, StatisticCode
 from .types import (
     CODE_SERVICES,
     PROFILE_LOOKUP,
@@ -37,6 +38,8 @@
     "PROFILES",
     "PROFILE_LOOKUP",
     "SERVICES",
+    "SiteTypeCode",
+    "StatisticCode",
     "get_channel",
     "get_codes",
     "get_continuous",

dataretrieval/waterdata/enums.py

@@ -0,0 +1,123 @@
+"""Enumerations for constrained waterdata API parameters.
+
+Using these enums is optional — plain strings are accepted everywhere — but
+they enable IDE autocompletion and make valid values discoverable without
+consulting the documentation.
+
+Examples
+--------
+>>> from dataretrieval.waterdata import SiteTypeCode, StatisticCode
+>>> df, _ = get_monitoring_locations(site_type_code=SiteTypeCode.STREAM)
+>>> df, _ = get_daily(statistic_id=StatisticCode.MEAN)
+"""
+
+from enum import Enum
+
+
+class SiteTypeCode(str, Enum):
+    """Site type codes for monitoring locations.
+
+    Codes correspond to the ``site_type_code`` parameter accepted by
+    :func:`~dataretrieval.waterdata.get_monitoring_locations` and related
+    functions.  The full reference table is available via
+    ``get_reference_table("site-types")``.
+    """
+
+    # Primary site types
+    AGGREGATE_GROUNDWATER_USE = "AG"
+    AGGREGATE_SURFACE_WATER_USE = "AS"
+    ATMOSPHERE = "AT"
+    AGGREGATE_WATER_USE_ESTABLISHMENT = "AW"
+    ESTUARY = "ES"
+    GLACIER = "GL"
+    WELL = "GW"
+    LAND = "LA"
+    LAKE = "LK"
+    OCEAN = "OC"
+    SUBSURFACE = "SB"
+    SPRING = "SP"
+    STREAM = "ST"
+    WETLAND = "WE"
+
+    # Facility secondary types
+    FA_ANIMAL_WASTE_LAGOON = "FA-AWL"
+    FA_CISTERN = "FA-CI"
+    FA_COMBINED_SEWER = "FA-CS"
+    FA_DIVERSION = "FA-DV"
+    FA_FIELD_PASTURE_ORCHARD_NURSERY = "FA-FON"
+    FA_GOLF_COURSE = "FA-GC"
+    FA_HYDROELECTRIC_PLANT = "FA-HP"
+    FA_LANDFILL = "FA-LF"
+    FA_OUTFALL = "FA-OF"
+    FA_PAVEMENT = "FA-PV"
+    FA_LABORATORY = "FA-QC"
+    FA_WASTEWATER_SEWER = "FA-SEW"
+    FA_SEPTIC_SYSTEM = "FA-SPS"
+    FA_STORM_SEWER = "FA-STS"
+    FA_THERMOELECTRIC_PLANT = "FA-TEP"
+    FA_WATER_DISTRIBUTION_SYSTEM = "FA-WDS"
+    FA_WASTE_INJECTION_WELL = "FA-WIW"
+    FA_WATER_SUPPLY_TREATMENT_PLANT = "FA-WTP"
+    FA_WATER_USE_ESTABLISHMENT = "FA-WU"
+    FA_WASTEWATER_LAND_APPLICATION = "FA-WWD"
+    FA_WASTEWATER_TREATMENT_PLANT = "FA-WWTP"
+
+    # Groundwater secondary types
+    GW_COLLECTOR_WELL = "GW-CR"
+    GW_EXTENSOMETER_WELL = "GW-EX"
+    GW_HYPORHEIC_ZONE_WELL = "GW-HZ"
+    GW_INTERCONNECTED_WELLS = "GW-IW"
+    GW_MULTIPLE_WELLS = "GW-MW"
+    GW_TEST_HOLE = "GW-TH"
+
+    # Land secondary types
+    LA_EXCAVATION = "LA-EX"
+    LA_OUTCROP = "LA-OU"
+    LA_PLAYA = "LA-PLY"
+    LA_SOIL_HOLE = "LA-SH"
+    LA_SINKHOLE = "LA-SNK"
+    LA_SHORE = "LA-SR"
+    LA_VOLCANIC_VENT = "LA-VOL"
+
+    # Ocean secondary type
+    OC_COASTAL = "OC-CO"
+
+    # Subsurface secondary types
+    SB_CAVE = "SB-CV"
+    SB_GROUNDWATER_DRAIN = "SB-GWD"
+    SB_TUNNEL_SHAFT_MINE = "SB-TSM"
+    SB_UNSATURATED_ZONE = "SB-UZ"
+
+    # Stream secondary types
+    ST_CANAL = "ST-CA"
+    ST_DITCH = "ST-DCH"
+    ST_TIDAL = "ST-TS"
+
+
+class StatisticCode(str, Enum):
+    """Common statistic codes used by the waterdata time-series endpoints.
+
+    Used in the ``statistic_id`` parameter of
+    :func:`~dataretrieval.waterdata.get_daily`,
+    :func:`~dataretrieval.waterdata.get_continuous`, and similar functions.
+    The full reference table is available via
+    ``get_reference_table("statistic-codes")``.
+    """
+
+    MAXIMUM = "00001"
+    MINIMUM = "00002"
+    MEAN = "00003"
+    AM = "00004"
+    PM = "00005"
+    SUM = "00006"
+    MODE = "00007"
+    MEDIAN = "00008"
+    STD = "00009"
+    VARIANCE = "00010"
+    INSTANTANEOUS = "00011"
+    EQUIVALENT_MEAN = "00012"
+    SKEWNESS = "00013"
+    TIDAL_HIGH_HIGH = "00021"
+    TIDAL_LOW_HIGH = "00022"
+    TIDAL_HIGH_LOW = "00023"
+    TIDAL_LOW_LOW = "00024"