HydroBASINS lev08 watershed · #7080039160
Bassin de Merrimack River
A watershed (drainage basin) is not a body of water — it is the land area where rainfall converges towards a single river that eventually reaches the sea (or an endorheic basin). Boundaries follow ridgelines.
Crosses 4 administrative regions : Essex, Hillsborough, Middlesex, Rockingham
Sub-basin area
960,2km²
Upstream area
13 016,3km²
Discharge
260,72m³/s
Mean elev.
50m
Administrative coverage
Hydrographic chain
▼ Drains into
Outlet (drains to ocean / endorheic)
▲ Receives from 2 basins
- Bassin de Assabet River1080 km²
- Bassin de Beaver Brook586 km²
4 dept-equivalent regions (GADM L2)
- 447.5 km²46.5% of basin
- 343.0 km²35.7% of basin
- 154.9 km²16.1% of basin
- Hillsborough9.8 km²1.0% of basin
30 intersecting protected areas
Marine Protected Area
3.32 km² overlap
Tewksbury State Hospital
IUCN Not AssignedConservation Easement
2.32 km² overlap
Reserve Program
1.40 km² overlap
Forest
1.01 km² overlap
Weir Hill
IUCN VReservation
0.79 km² overlap
Powwow River
IUCN VConservation Easement
0.59 km² overlap
Finch-Topping
IUCN VConservation Easement
0.56 km² overlap
Agricultural Conservation Easement Program - Wetland Reserve Easements (ACEP-WRE), Rockingham, NH
IUCN Not AssignedConservation Easement
0.49 km² overlap
Perkins
IUCN VConservation Area
0.45 km² overlap
21 more protected areassorted by overlap area
Hunt Road
IUCN VTown Forest
0.41 km² overlap
Webster Wildlife +
IUCN VNatural Area
0.35 km² overlap
Greenbelt D
IUCN VLocal Conservation Area
0.34 km² overlap
Bradford Street
IUCN VConservation Area
0.34 km² overlap
Unknown
IUCN VPark
0.33 km² overlap
Carr Island
IUCN VSanctuary
0.28 km² overlap
Bailey CR
IUCN Not AssignedConservation Easement
0.25 km² overlap
Meadow Pond WCE
IUCN Not AssignedPond
0.24 km² overlap
Ordway Reservation Cr
IUCN VReservation
0.22 km² overlap
Arden CR
IUCN Not AssignedConservation Easement
0.21 km² overlap
Den Rock Park CR
IUCN Not AssignedPark
0.21 km² overlap
McPherson Woodlot
IUCN VConservation Area
0.21 km² overlap
State Conservation Area
0.21 km² overlap
Veasey
IUCN VPark
0.19 km² overlap
Ritchie CR
IUCN Not AssignedConservation Easement
0.19 km² overlap
Greenbelt C
IUCN VLocal Conservation Area
0.19 km² overlap
Brox CR
IUCN Not AssignedConservation Easement
0.18 km² overlap
Local Conservation Area
0.17 km² overlap
Reserve Program
0.16 km² overlap
Middle Street
IUCN VConservation Area
0.16 km² overlap
Stevens Coolidge Place
IUCN VReservation
0.15 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
4 668 distinct species · 511 124 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 35 species (selected proportionally per kingdom among those with at least one documented interaction here) to keep the graph readable. Hover for details, click to explore the full ecosystem of a species.
ℹ️ The territory contains many more species than displayed and all their documented interactions: the graph is intentionally the structural skeleton (top-N species by composite local score, edges filtered by Serrano 2009 disparity filter α=0.2).
Indicateurs du tissu écologique
Tissu écologique de Bassin de Merrimack River : 23 espèces reliées par 80 interactions GloBI sur 4 types (connectance 12.7%, filtre Serrano α=0.2). 13 bulles taxonomiques (cascade genre/famille GloBI, ≥3 espèces).
Comparaison sur la connectance du réseau local complet vs distribution nationale (toutes les communes françaises).
Hydroclimate (BasinATLAS lev08)
Mean T°
8,9°C
Annual rain
1 115mm
Moisture idx (CMI)
0,13
Runoff
771mm/an
PET
970mm
AET
751mm
Mean slope
2,1°
Water table
119cm
Forest
71%
Crops
3%
Urban
41%
Protected
1%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)