WBD HU4 0109 Massachusetts-Rhode Island Coastal Updates
The Watershed Boundary Dataset has been updated in several areas along the Massachusetts and Rhode Island coast. Updates for this area are included in the latest version of the WBD data available via the National Hydrography Dataset website.
WBD HU4 0109 represents the coastal drainage areas along the Massachusetts and Rhode Island coast extending from the Merrimack River to the north and the Long Island Sound to the south (Figure 1). Coastal frontal areas within the WBD represent multiple hydrologic systems that contribute to the same coastal feature such as a particular ocean, bay or sound. Currently, WBDHU4 0109 has areas contributing flow to both the Atlantic Ocean and Long Island Sound (Figure 1).
Upon further investigation it was discovered that 8-digit Hydrologic Unit (WBD HU8) 01090005: Pawcatuck-Wood represents the drainage areas for Wood River (HU10 0109000501) and Pawcatuck River (HU10s 0109000502 and 0109000503) which flows into Long Island Sound as well as the frontal area flowing into the Atlantic Ocean and Block Island (HU10 0109000504). (Figure 2)
Through collaboration and coordination efforts with USGS Hydrography Leads, WBD National Technical Coordinators, WBD State Stewards, State and Local partners it was decided that WBD HU4 0109 and WBD HU4 0110 would be updated so HU4 0109 would represent areas flowing into the Atlantic Ocean and 0110 would represent areas flowing into Long Island sound. In order to accomplish this HU8 01090005 would be retired and the Wood River and Pawcatuck River HU10 units would be moved into a new HU8 unit 01100007 and the remaining portion of 01090005 would be grouped into a new frontal HU8 unit 01090006 (Figure 3). Table 1 represents the original hydrologic codes and updated codes for this region.
| Original HU Code | Original Name | Updated Code | Updated Name |
|---|---|---|---|
| 1090005 | Pawcatuck-Wood | 1090006 | Point Judith-Block Island |
| 1090005 | Pawcatuck-Wood | 1100007 | Pawcatuck River |
| 109000501 | Wood River | 110000701 | Wood River |
| 109000502 | Upper Pawcatuck River | 110000702 | Upper Pawcatuck River |
| 109000503 | Lower Pawcatuck River | 110000703 | Lower Pawcatuck River |
| 109000504 | Block Island-Frontal Block Island Sound | 109000601 | Point Judith Pond-Frontal Block Island Sound |
| 109000504 | Block Island-Frontal Block Island Sound | 109000602 | Block Island-Block Island Sound |
| 10900050101 | Upper Wood River | 11000070101 | Upper Wood River |
| 10900050102 | Lower Wood River | 11000070102 | Lower Wood River |
| 10900050201 | Chipuxet River-Pawcatuck River | 11000070201 | Chipuxet River-Pawcatuck River |
| 10900050202 | Usquepaug River | 11000070202 | Usquepaug River |
| 10900050203 | Beaver River | 11000070203 | Beaver River |
| 10900050204 | Usquepaug River-Pawcatuck River | 11000070204 | Usquepaug River-Pawcatuck River |
| 10900050205 | Tomaquag Brook-Pawcatuck River | 11000070205 | Tomaquag Brook-Pawcatuck River |
| 10900050301 | Ashaway River | 11000070301 | Ashaway River |
| 10900050302 | Shunock River | 11000070302 | Shunock River |
| 10900050303 | Outlet Pawcatuck River | 11000070303 | Outlet Pawcatuck River |
| 10900050401 | Saugatucket River | 10900060101 | Saugatucket River |
| 10900050402 | Point Judith Pond-Frontal Block Island Sound | 10900060102 | Point Judith Pond-Frontal Block Island Sound |
| 10900050403 | Ninigret Pond-Frontal Block Island Sound | 10900060103 | Ninigret Pond-Frontal Block Island Sound |
| 10900050404 | Block Island | 10900060201 | Block Island |
| 10900050405 | Rhode Island Sound-Block Island Sound | 10900060202 | Rhode Island Sound-Block Island Sound |
| 10900050406 | Point Judith Harbor of Refuge-Block Island Sound | 10900060104 | Point Judith Harbor of Refuge-Block Island Sound |