Question: Which river flows through the valley with which the AM radio station WWJZ serves?
Context: WWJZ (640 kHz) is an AM radio station licensed to Mount Holly, New Jersey, serving Philadelphia and the Delaware Valley.  The station airs Catholic talk programming and is owned and operated by Relevant Radio. The Akatarawa Valley is a valley in the Tararua Range of New Zealand's North Island.  It provides a link from the upper reaches of the Hutt Valley to Waikanae on the Kapiti Coast through rugged hill country.  The valley is lowly populated and contains the localities of Reikorangi and Cloustonville.  At the Hutt Valley end, the Akatarawa Valley is rugged and the Akatarawa River flows through it.  The terrain is less difficult at the Kapiti end, where the Waikanae River flows through part of the valley on its route from its headwaters in the Tararuas to the Tasman Sea, and is met in the valley by tributaries such as the Ngatiawa River and the Reikorangi Stream. The Gila River Valley is a multi-sectioned valley of the Gila River, mostly in Arizona.  The Gila River forms in western New Mexico and flows west across southern-eastern, south-central, and southwestern Arizona; it changes directions across the state, and defines specific areas and valleys.  The central portion of the river flows on the southern Phoenix valley region-(where Phoenix, in the "Salt River Valley" joins the Gila River Valley), and the final sections in southwestern Arizona form agricultural, irrigated smaller valleys within the Gila River valley, (for example Dome Valley, Mohawk Valley, and Hyder Valley). Segen is a river that arises from Delo Mountain, central Amarro, Ethiopia.  The river flows to the east, then to the north and to the west and last to the south to join the Weito River.  On the western side of Amarro horst the valley through which the river flows is called Segen Valley. The Mahoning Valley is a geographic valley encompassing the area of northeast Ohio and northwest Pennsylvania that drains into the Mahoning River.  The Mahoning and Shenango Rivers empty into the Beaver River, which empties into the Ohio River.  The Mahoning River flows through Lawrence County and the Shenango River flows through Mercer County in Pennsylvania, and then the Mahoning River flows from Stark, Mahoning, Trumbull, and Portage counties in Ohio.  The three main tributaries of the Mahoning River are Mosquito Creek, West Branch, and Eagle Creek, all in Ohio.  It is often refereed to by local as the "Ho". Poxte is a river and valley of the Maya Mountains in Guatemala.  The valley is noted for numerous Maya sites such as Ixtutz and the Petén Caves.  The river is located on the southwest of the Dolores plateau and northwest of Poptún, in the Guatemalan department of Petén.  The source of the river is on the same plateau, near the villages of Boca del Monte and Santo Domingo.  The river flows westwards through the hamlet of Poxte, it then disappears amongst the karst topography and resumes its course 7 km to the west.  It continues westwards into the San Juan River, which is a tributary of the Machaquila River.  The Machaquila River feeds into the Pasión River, which flows into the Usumacinta River and into the Gulf of Mexico.  The upper reaches of the Poxte River shares its drainage with the Mopan River, which flows eastwards into the Caribbean Sea. The Delaware Valley is the valley through which the Delaware River flows.  By extension, this toponym is commonly used to refer to Greater Philadelphia or Philadelphia metropolitan area ("the [Lower] Delaware Valley Metropolitan Area"), which straddles the Lower Delaware River just north of its estuary.  The Delaware Valley Metropolitan Area is located at the southern part of the Northeast megalopolis and as such, the Delaware Valley can be described as either a metropolitan statistical area (MSA), or as a broader combined statistical area (CSA).  The Delaware Valley Metropolitan Area is composed of several counties in southeastern Pennsylvania and southwestern New Jersey, one county in northern Delaware and one county in northeastern Maryland.  The MSA has a population of over 6 million, while the CSA has a population of over 7.1 million (as of the 2010 Census Bureau count).  Philadelphia, being the region's major commercial, cultural, and industrial center, wields a rather large sphere of influence that affects the counties that immediately surround it. The Evinos (Greek: Εύηνος ) is a 92 km long river in western Greece, flowing into the Gulf of Patras.  Its source is in the northern Vardousia mountains, near the village Artotina, Phocis.  The river flows in a generally southwestern direction, for most of its length in Aetolia-Acarnania.  It feeds the reservoir of Lake Evinos, that is about 10 km².  The river flows through a deep forested valley with few small villages.  In its lower course it flows through lowlands, and it empties into the Gulf of Patras 10 km southeast of Missolonghi.  The village Evinochori near its mouth owes its name to this river. Sira is a river in southwestern Norway.  The 152 km long river flows begins in the Sirdalsheiane mountains near the borders of Aust-Agder, Vest-Agder, and Rogaland counties.  The headwaters of the river is the lake Ytre Storevatnet and it flows south through the Sirdalen valley in the municipalities of Sirdal and Flekkefjord.  The river flows through the large lakes Sirdalsvatnet and Lundevatnet before heading south on the Vest-Agder/Rogaland county border.  At the village of Åna-Sira the river empties into the Åna fjord.  The river runs through several large villages such as Åna-Sira, Sira, Tonstad, Lunde, and Kvæven.  The river drains the 1902.7 km2 watershed.  The Tonstad Hydroelectric Power Station is powered by water from the waterfalls along this river. The Panjshir River flows through the Panjshir Valley in northeastern Afghanistan, 150 km north of Kabul.  Its main tributary is the Ghorband River which flows from the Parwan Province and joins the Panjshir River 10 km east of Charikar.  The Panjshir River flows southward through the Hindu Kush and joins the Kabul River at the town of Surobi.  A dam was built on the Panjshir River near Surobi in the 1950s to supply water from the Panjshir River to the Kabul River.
Answer: Delaware River